Smooth Cuticle Research Articles

Micromorfologia Foliar de Espécies de Sida spp. (guanxumas)

A eficácia dos herbicidas aplicados à folha é influenciada pela morfologia da superfície foliar que recebe a calda. A topografia da superfície foliar, o grau e o tipo da formação da cera epicuticular e a presença, tipo e distribuição de tricomas são características que influenciam a distribuição da calda pulverizada sobre a superfície foliar e, conseqüentemente, a eficácia do controle da planta daninha. Diante desses fatos, o presente trabalho teve como objetivo conhecer morfologicamente a superfície foliar de três espécies de guanxuma (Sida rhombifolia , Sida glaziovii e Sida cordifolia ). A pesquisa foi desenvolvida no Núcleo de Apoio à Pesquisa em Microscopia Eletrônica Aplicada à Pesquisa Agropecuária (NAP/MEPA), instalada na ESALQ/USP-Piracicaba/SP. As amostras biológicas foram fixadas, posteriormente desidratadas, secas ao ponto crítico e recobertas com ouro. Após a evaporação com metal, as amostras das folhas foram observadas em microscópio eletrônico de varredura Zeiss, operando entre 5 e 15 kV. Verificou-se que a superfície adaxial das espécies S. rhombifolia e S. glaziovii apresentou tricomas estelares e simples (não-ramificados), tanto curtos como longos, e também glandulares simples, tanto curtos como longos; S. glaziovii apresentou a maior quantidade destes. A espécie que apresentou maior presença de ceras epicuticulares foi S. rhombifolia, cuja aparência é estriada e a orientação aleatória. Das três espécies, S. cordifolia foi a que mostrou menor quantidade de tricomas, possuindo na superfície adaxial predominantemente tricomas simples e/ou com duas ramificações e também tricomas glandulares simples e curtos. A cutícula apresentou superfície plana e lisa, sem o aspecto estriado das outras duas espécies analisadas. Todas as espécies são anfiestomáticas, com predominância do tipo anomocítico, que é característico da família Malvaceae.

Ultrasculpture of achene surface in Polygonum section Polygonum (Polygonaceae) in Russia

Based on SEM examination of 47 specimens and 33 species from Russia and Europe, this is a survey of achene surface ultrasculpture in 6 subsections of annual species of Polygonum. Early and late achenes detected in most species possess sound distinctions in achene shape, size, color and exocarp structure. Late achenes with early and fast seed germination preserve exocarp structure typical for premature achenes of both types: thin colorless walls and vast cavities, thin cuticle and insignificant wax deposits. Early achenes destined for long‐term preservation in soil are thickwalled and covered with thick and smooth cuticles and wax layers. The structure of achene surfaces changes substantially during maturing, especially in early achenes: coarse or foveo‐rugulate background becomes minutely rough, foveosmooth or minutely reticulate. Verrucae are not obligatory ornaments. Depending on their location and arrangement of exocarp cells the surface is evenly verrucate (subsect. Paatula Tzvel.), linear‐verrucate (subsect. Salsuginea Tzvel.) or striate‐verrucate (subsect. Humifusa Tzvel., most species in subsect. Polygonum). Smooth and glossy achenes are more common in permanently wet environments (subsect. Maritima Tzvel., Arenaria Tzvel., P. arenastrum and P. calcatum from subsect. Polygonum). In places with fluctuating availability of water the achenes have heavier sculpturing and thicker cutin and wax coverings. A broad range of surface sculptures in some species and their similarity across taxonomically distant taxa decrease the value of the characters for taxa identification.

Structure and ultrastructure of leaf and calyx glands in Galphimia brasiliensis (Malpighiaceae)

The present study describes the anatomical structure of calyx and leaf glands in Galphimia brasiliensis and analyzes the mechanism of secretion. The glands are marginal and suprabasal, cup-shaped, sessile, and scarcely visible with the naked eye. Light microscopy reveals the following features: a thin, smooth cuticle; unistratified secretory cells; subglandular parenchyma; and vascular bundle supply composed of phloem and xylem with abundant druses of calcium oxalate. Transmission electron microscopy reveals the presence of secretory cells with conspicuous nuclei, dense cytoplasm, lipid droplets, numerous vesicles, mitochondria, Golgi, rough endoplasmic reticulum (RER), and elongated plastids with osmiophilic contents. The secretion reaches the apoplastic space and accumulates beneath the cuticle. Finally, the viscous, translucent exudate is eliminated by mechanical rupture of the cuticle. Histochemical analysis confirms that lipids are the main constituent. Small amounts of polysaccharides were also identified.

Redescription of Ichthyofilaria argentinensis Incorvaia, 1999 (Nematoda: Philometridae) parasite of Merluccius hubbsi (Pisces: Merlucciidae) from Argentina.

Ichthyofilaria argentinensis Incorvaia, 1999 (Nematoda: Philometridae) is redescribed from type specimens and from parasites collected from the swim bladder of Argentine hakes Merluccius hubbsi Marini, 1933 caught at the Gulf of San Jorge (46 degrees 30'S, 66 degrees 30'W), Argentine Sea, in July, 1998. Sixteen out of 80 hakes (20%) were found to be parasitised by gravid females of this philometrid. After revision of both these nematodes and type material, the following differences from the original description of the species were observed: (a) cuticle with fine transverse striations, instead of smooth cuticle; (b) presence of cephalic papillae and a pair of amphids; (c) absence of swellings in the oesophagus; (d) oesophageal gland appendix very large and lobulate rather than small and vermiform, and (d) presence of vulva and vagina. The morphological features given in the redescription allow the confirmation of the identity of I. argentinensis as a valid species and to distinguish it from other members of the genus.

Mutual antagonism between signals secreted by adjacent wingless and engrailed cells leads to specification of complementary regions of the Drosophila parasegment.

Specialized groups of cells known as organizers govern the establishment of cell type diversity across cellular fields. Segmental patterning within the Drosophila embryonic epidermis is one paradigm for organizer function. Here cells differentiate into smooth cuticle or distinct denticle types. At parasegment boundaries, cells expressing Wingless confront cells co-expressing Engrailed and Hedgehog. While Wingless is essential for smooth cell fates, the signals that establish denticle diversity are unknown. We show that wg mutants have residual mirror-symmetric pattern that is due to an Engrailed-dependent signal specifying anterior denticle fates. The Engrailed-dependent signal acts unidirectionally and Wg activity imposes this asymmetry. Reciprocally, the Engrailed/Hedgehog interface imposes asymmetry on Wg signaling. Thus, a bipartite organizer, with each signal acting essentially unidirectionally, specifies segmental pattern.

Ichthyofilaria argentinensis sp. nov. (Nematoda: Philometridae) parasite of Merluccius hubbsi (Pisces: Merlucciidae)

The present work deals with a new nematode species, Ichthyofilaria argentinensis, found in the swim bladder of the Argentine common hake, Merluccius hubbsi Marini, 1933, from the Southwest Atlantic sector between 34º and 48ºS. Ichthyofilaria argentinensis sp. nov. is characterized by its smooth cuticle and fusiform body. The mouth is simple and does not have lips. The robust oesophagus is divided into two sections, an anterior muscular and a posterior glandular, from which a free glandular appendage arises, directed backwards.

Ventral Cuticle Pattern Formation in Drosophila Embryos (Abstract)

Wild type Drosophila embryos secrete a segmentally repeating pattern of cuticular structures. The ventral surface of each abdominal segment is covered with a belt of denticles, consisting of 6 rows of uniquely oriented, morphologically distinct denticles in the anterior of each segment, and an expanse of naked cuticle covering the posterior of each segment. The intrasegmental patterning in the Drosophila embryo is regulated by cell-cell communication. Segment polarity genes in Wingless (Wg) and Hedgehog (Hh) signaling pathways are functionally required for this patterning process. One hypothesis postulates that the mutual interdependence and maintenance of Wg and Hh expression along the parasegmental boundary can be a center for secreted factors, for example Wg. The distribution of Wg can influence cell identities in all rows of epidermal cells in the 10-12-cell-wide segment. In the absence of Wg signaling, both aspects of wild-type pattern become defective: Wg mutants show reduced denticle diversity and no naked cuticle specification. It is suggested that Wg signaling promotes the diversity of denticle types present in the anterior denticle belt and the smooth or naked cuticle constituting the posterior surface of the segment. At the presence of high concentration of Wg, or in gain-of-function condition, naked cuticles are formed. This naked cuticle cell fate is specified by a cellular pathway distinct from the denticle diversity-generating pathway. Though the naked cuticle formation is proposed to be the outcome of one of the Wg functions, the determination of denticle formation is lack of description. We first report here a novel Drosophila gene, tumbler (tum), whose gene activity is required for denticle formation. Based on the interactions among Wg/Hh signaling genes and tum, we propose that the cell fate determination in Drosophila embryonic ventral epidermis is the outcome of competition between Wg/Hh signaling activity for naked cuticle formation and Tum gene activity for denticle formation. We will also describe a new Hh signaling gene, taroid (tr). Patched (Ptc) and Smoothened (Smo) form a bipartite receptor complex of Hh signal. The Hh molecule binding to Ptc can relieve the inhibition of Smo activity by Ptc. Genetically, the flow of signaling is from hh to ptc to smo. While tr is downstream of hh, it is genetically acting upstream of or parallel to ptc. Unexpectedly, tr can enhance the loss-of-function phenotype of smo, but is genetically downstream of smo. Among possibilities, it is very likely that Tr, PTc and Smo are acting in a parallel manner. In addition, the removal of tr gene function from imaginal discs does not affect the expression of Hh target gene. With other evidences, we speculate that Tr may be a novel Hh receptor, which directs a novel signaling pathway independent of Smo activity in embryos.

Austral Hepaticae 29. More New Taxa and Combinations in Telaranea (Lepidoziaceae) and a New Name for Frullania caledonica (Schuster) Schuster (Frullaniaceae) from New Caledonia

Telaranea consobrina, T fragilis, and T palmata, new species from Australasia, are described and illustrated. Telaranea clatritexta (Stephani) Engel & Merrill and T quadricilia (Stephani) Engel & Merrill of Australasia and T. fernandeziensis (Stephani) Engel & Merrill from Juan Fernmindez are new combinations. Frullania neocaledonica of New Caledonia is proposed as a new name for Frullania caledonica (Schuster) Schuster, an illegitimate name. The following new taxa and new combinations, together with those previously published (Engel & Merrill, 1995), are the result of a phylogenetic study of the genus Telaranea, which is currently in preparation by the authors. The names are here published separately to make them immediately available for use. Studies on Australasian Hepaticae have also revealed a nomenclatural change required in the genus Frullania. Telaranea clatritexta (Stephani) Engel & Merrill, comb. nov. Basionym: Lepidozia clatritexta Stephani, Spec. Hep. 3: 583. 1909. TYPE: Australia. Western Australia: Swan River, Drummond, ex Herb. Kew (G). Lepidozia complanata Herzog, Memoranda Soc. Fauna F1. Fenn. 27(1950-1951): 92. fig. 39. 1952. Syn. nov. Telaranea complanata (Herzog) Engel & Merrill, Phytologia 79: 251. 1995 [June 1996]. TYPE: Australia. Western Australia: without specific loc., Goebel (holotype, not seen). In a previous paper (Engel & Merrill, 1995), we published the combination Telaranea complanata (Herzog) Engel & Merrill. Further studies have revealed that Lepidozia clatritexta Stephani is the same taxon, and a transfer to Telaranea is therefore required. Telaranea consobrina Engel & Merrill, sp. nov. TYPE: Tasmania. Eastern slope of Black Bluff just below summit, S of Bumrnie, 1250 m, 21 Mar. 1977, Engel 15799 (holotype, F; isotype, HO). Figure 1. Species nova T. meridianae affinis disco folii basin versus 8 cellulis lato, lobis angustioribus, amphigastriis latioribus brevioribusque, hyalodermate conspicuo differt. Plants soft and flexuous, ascending to suberect, pale green, medium in size, to 6 mm wide, including branches. Branching rather regularly 1-pinnate, the branches of the Frullania-type, at times becoming flagelliform; first branch underleaf undivided (very rarely bilobed), broadly acuminate to lanceolate. Ventral-intercalary branches not seen. Stems with cortical cells distinctly differentiated, thinwalled, in 13-14 rows; cortical cells in section slightly to distinctly larger than the numerous (4953) medullary cells. Leaves on main shoot obliquely spreading, contiguous, the disc plane or weakly convex, the lobes ventrally decurved, the insertion distinctly incubous, the disc broader than high; leaves 475-600 /m wide x 440-525 /m long, the leaves 4(5)-lobed to 0.4-0.5, the lobes straight to moderately divergent. Lobes narrowly acute to acuminate, 4-5 cells wide at base, often 4 cells wide in basal sector, then biseriate for 2-3 tiers, terminating in a short uniseriate row of 2-3 cells (or sporadically a single cell or 2 laterally juxtaposed cells); lobe cells ? isodiametric to short rectangular, thin-walled. Leaf disc somewhat asymmetrically cuneate, the disc (5)6-7(8) cells high (from median sinus base to leaf base), 13-16 cells wide in distal portion narrowing to 8(9) cells wide in basal portion. Cells of disc thin-walled, median cells short rectangular, 24-38(42) /m wide x 42-49 /m long, the cells in + irregular rows; cuticle smooth. Underleaves somewhat smaller than leaves, 1.7-2.3x stem width, 4(5)-lobed to 0.4-0.45, the lobes narrowly acut , 3-4 cells wide at base and biseriate for 1-2 tiers, ending in a uniseriate row of 2-3 short cells; disc symmetrically broadly cuneate (wider than high), 4-5 cells high (median sinus), 14-18 cells wide. Asexual reproduction lacking. Androecia and gynoecia not seen. Taxonomy. This species strongly resembles T meridiana of New Zealand, with broad, almost lonNOVON 9: 339-344. 1999. This content downloaded from 207.46.13.110 on Fri, 09 Dec 2016 05:48:26 UTC All use subject to http://about.jstor.org/terms

Austral Hepaticae. 28. Plagiochila bazzanioides Engel & Merrill, a Remarkable New Species of Plagiochilaceae from New Zealand

Plagiochila bazzanioides, a new species from New Zealand, is described and illustrated. Plagiochila is the largest genus of hepatics, with perhaps as many as 1600 described species (Bonner, 1962). As in other species-rich groups, the actual number of species will probably prove to be considerably less. According to Schuster (1980: 348), total number of valid species of Plagiochila may prove to be below 500. The genus is widely distributed and essentially cosmopolitan. Centers of taxic diversity are chiefly in the Neotropics and southeast Asia, and the genus is rather poorly represented in temperate areas. For example, Schuster (1980) included 20 species for North America, and Inoue and Schuster (1971) included 25 species from temperate Australasia. This paper describes an additional distinctive species occurring in New Zealand, as follows. Plagiochila bazzanioides Engel & Merrill, sp. nov. TYPE: New Zealand. North Island: North Auckland Province, Rangitoto Island, immediately E of Auckland, 50-160 m, 4 Feb. 1995, Engel 20769 (holotype, F; isotype, CHR). Figure 1. Species insignis foliis falcatis canaliculatis decurvatis, marginis foliorum pectinatis dentibus gracilibus uncinatis, ramis plurimis flagelliformibus, androeciis intercalaribus, paraphylliis caulis dentatis lamelliformibus a species nobis notis optime distincta. Plants bazzanioid in habit, ascending, without differentiation of a horizontal leafless axis, rich, deep olive green; leafy shoots medium, to 5 mm wide. Stems with paraphyllia inconspicuous, typically consisting of a single, short, sharply toothed lamella adjacent to dorsal leaf base; stem in cross section with cortical cells in (2)3 layers of very thick-walled cells, the medullary cell walls thin, colorless. Branching exclusively lateral-intercalary, sometimes with geotropic, microphyllous, rhizoidous, flagelliform, lateral-intercalary branches. Rhizoids rather dense on leafy shoots. Leaves horizontally spreading to ventrally secund, often conspicuously falcate, spreading at + right angles to stem, closely imbricate, frequently canaliculatesubtubular to the tips, the dorsal margins narrowly recurved and forming a distinct convex fold, lending the shoot a tightly pleated aspect in dorsal view, in ventral aspect the ventral margin aligned at right angles to the stem except for the basal sector, which lies parallel to the stem, in ventral view the ventral margins pectinate-toothed, the teeth often stiffly reflexed and hooked dorsally, the ventral surface of stem moderately or totally hidden; leaf insertion elongated, distinctly straight and steeply oblique for most of its length, abruptly recurved at ventral end; leaves asymmetrically narrowly elongate-trapezoidal, tapering to a markedly narrow, almost parallel-sided distal 0.2 to 0.3; leaf apex narrowly rounded to truncate, tending to become bidentate by 2 conspicuous, often diverging apical teeth that are often larger than adjacent teeth; dorsal margin nearly straight to broadly curved inward, with + regularly spaced, slender, recurved teeth to the base (best seen in ventral aspect); ventral margin + straight from a subauriculate base, conspicuously ciliate-dentate particularly in basal portion, the teeth stiffly reflexed (hooked dorsally), the margin often entire or subentire in the distal 0.5, decurrent, the decurrent strip dentate. Marginal teeth slenderly acuminate, 1-2 cells wide at the base, consisting almost entirely of a uniseriate row of 46 distinctly thick-walled cells, the terminal cell elongate, to 4.2:1. Underleaves consisting of an amorphous clump of cells, in part short-filamentous, at end of decurrent ventral leaf base. Cells in median portion of leaf thin-walled and with trigones bulging to knotlike; median cells 20-29 /m wide x 30-36 /m long; cells of leaf bases scarcely elongated and not forming a basal field; cuticle smooth. Asexual reproduction lacking. $ Plants + smaller than the Y ones, mostly simple; androecia on main shoot and leading lateralintercalary branches, becoming intercalary in position (often with several successive androecia occurring on a stem or branch); bracts many, in up to 15 pairs, strongly saccate in dorsal half of base; apex broadly rounded, spatulate, entire; ventral marNovoN 9: 29-31. 1999. This content downloaded from 207.46.13.126 on Sat, 24 Sep 2016 04:54:34 UTC All use subject to http://about.jstor.org/terms

Studies on Plagiochila sect. Tayloriae in Asia

Studies on Plagiochila sect. Tayloriae in Asia

Four freshwater eutardigrades from Korea with description ofisohypsibius brevitubulatusn. sp.

As a result of examining the specimens collected from various freshwater bodies since 1995, four eutardigrades are added to Korean fauna: isohypsibius brevitubutatus n. sp., I. baldii (Ramazzotti), I. marcellinoi (Binda and Pilato), and Diphascon (Diphascon) higginsi Binda. I. brevitubulatus n. sp. differs from its congeners by having a combination of the following characteristics: smooth cuticle, rather big body size, short and broad buccal tube, presence of lunules, and pharynx bearing 3 rod‐like macroplacoids without microplacoid. All the species are illustrated and briefly commented on their habitats with the associated fauna.

Anatomical changes and evolutionary trends in the foliar epidermis of extant and fossil Euro-Mediterranean oaks (Fagaceae)

The differentiation of foliar epidermis structures, cuticles, stomata, and indumentum of most of the extant Euro-Mediterranean taxa ofQuercus have been studied by light and scanning electron microscopy, and compared with other genera and fossil material. Results allow the recognition of the subgg.Sclerophyllodrys, Cerris andQuercus, and of various sections and even individual species. The cyclocytic stomata type, regarded as plesiomorphic, is found in the geologically oldest representatives of the familiy (Dryophyllum, resp.Eotrigonobalanus) and in the relatively old, evergreen to semi-evergreen species ofQuercus subgg.Sclerophyllodrys andCerris. These taxa also have relatively thick and smooth cuticles. Anomocytic stomata, thinner cuticles and the presence of crystalline wax flakes are regarded as apomorphic features and characterize the deciduous taxa of subg.Quercus. These changes are interpreted as ecological adaptations to the changing climates from the Tertiary to the present. An analysis of the various character combinations found in macrofossils and the often poor species separation inQuercus suggest that hybridization has played a major role in the evolution of the Euro-Mediterranean oaks.

Divergent Host Relationships of Males and Females in the Parasitoid Encarsia porteri (Hymenoptera: Aphelinidae)

Heterotrophic parasitoids have been reported in the aphelinid genus Encar- sia. These are species in which females develop as primary internal parasitoids of whitefly and males develop as primary internal parasitoids of lepidopteran eggs. The obligate nature of the host relationships in these aphelinids has been questioned and was investigated in this study. We examined the oviposition of female Encarsia porteri (Mercet) in 3 host types: bollworm eggs (Helicoverpa zea (Boddie)), sweetpotato whitefly nymphs (Bemisia tabaci (Gennadius)), and early pupal wasps (E. porteri). Although males of most Encarsia species develop on wasp pupae as hyperparasitoids, female E. porteri did not generally oviposit in wasp pupae. Whitefly nymphs were parasitized almost exclusively by mated females, whereas both mated and un- mated females oviposited in moth eggs. The suitability of the above hosts as well as pupal E. fonnosa were also investigated for the development of male progeny. Males were produced only on moth eggs. Thus, we conclude that the heterotrophic host relationships of E. porteri are indeed obligate. Larval E. porteri are sexually dimorphic. Early instars of male larvae have a sculptured cuticle, bear long spines along the venter, and have horn-like projections on the head capsule. Females, in contrast, are more typically hymenopteriform with weak scleroti- zation of the head capsule, indistinct segmentation, and a smooth cuticle. Also, although both male and female early instar larvae are enclosed within a membrane, only females are envel- oped by an opaque cellular layer within this membrane. WHEN 2 OR more disparate kinds of food or hab- itat are required to maintain a population, the re- sources are generally used in sequence by mor- phologically specialized life stages. Less commonly, male and female immature stages may be special- ized on different resources; these systems have been called by Walter (1983a). In heteronomous species, male and female larval morphology and behavior may be very different and may evolve more or less independently (Slat- kin 1984). Like systems in which morphological specialization occurs within the same sex but in different generations, the evolution of sexual di- morphism in heteronomous species is not subject to the same sorts of developmental constraints as in species with sequential specialization. Multige- nerational and heteronomous morphological spe- cialization is constrained only by the different forms having genes in common (Moran 1994).

Freshwater nematodes of the Gal�pagos

Freshwater nematodes of the Galapagos archipelago were studied from four samples collected in 1988. Eighteen species, two of which are new to science, belonging to five orders, Enoplida, Dorylaimida, Mononchida, Monhysterida and Chromadorida, are described. Alaimus wittmeri n.sp. is characterised by having a smooth cuticle, a more posteriorly enlarged pharynx, a posteriorly situated amphidial fusus, obscure but anteriorly situated excretory pore, a mono-opisthodelphic ovary, and by the absence of sexual dimorphism in the lip region, the absence of pre-vulval uterine sac, the presence of males that have few (4–7) and weak ventromedian supplements and absence of mucro on tail tip. Monhystera floreanae n. sp. is distinguished by its females having a small body (L = 492–634 µm) with a narrow lip region, narrow posteriorly located amphidial openings, a small value for the c'-ratio (c' = 6.0–7.5), weak vaginal sphincter, by the absence of post-vaginal gland cells, absence of males and absence of crystalloid bodies. The difficulty in the use of crystalloid bodies as diagnostic character in the genus Monhystera is discussed. Two forms, a big form and a small form, which are similar except in measurements are reported for Achromadora micoletzkyi. SEM photos of ruptured cuticle of A. micoletzkyi and A. semiarmata show unique intra-cuticular structures. Comparison of these structures in the two species is made. Papilliform instead of setiform outer labial sensilla are also observed in A. micoletzkyi. The presence of the male and fine crystalloid bodies in Achromadora semiarmata, dorsal body pore in Prismatolaimus dolichurus and Prismatolaimus kenyensis, forty longitudinal cuticular ridges around the mid-body of Stomachoglossa pachyderma, crystalloid bodies in Ironus dentifurcatus are reported here for the first time. SEM photos of twelve species: Monhystera floreanae n. sp., Monhystera somereni, Alaimus wittmeri n. sp., Monhystrella hastata, Paramphidelus dolichurus, Eutobrilus annetteae, Ironus dentifurcatus, Chronogaster cameroonensis, Rhabdolaimus terrestris, Stomachoglossa pachyderma, Achromadora micoletzkyi and Achromadora semiarmata, are also presented. The richest nematode fauna was found in El Junco (San Cristobal), the only permanent freshwater lake on the archipelago. The nine species recorded from the lake are probably only a fraction of the total nematode fauna. The very recent man made reservoir La Toma has a relatively high diversity, due to its vicinity to El Junco. It is argued that the freshwater nematodes from San Cristobal probably arrived there through passive transport by birds. The freshwater bodies encountered on Floreana are very different from those on San Cristobal and so is their nematode fauna. Part of the species found on these islands may have been transported by land birds, others may have invaded the freshwater from terrestrial habitats. Apart from the two new species, the other ones have a wide to very wide distribution (cosmopolitan, southern hemisphere, ...), so that endemism of freshwater nematodes is very low, if it exists at all. This is due to easy dispersal capacities of nematodes on the one hand and the recent colonization (not more than 10 000, max. 40 000 years) on the other hand.

Antennal sexual dimorphism in Diabrotica virgifera virgifera (Le Conte) (Coleoptera : Chrysomelidae): Male specific structures, ultrastructure of a unique sensillum, and sites of esterase activity

Morphological and histochemical studies were performed on the flagellar antennal segments of adult Diabrotica virgifera virgifera LeConte (Coleoptera : Chrysomclidae). The work was part of a program to investigate the biological significance of a soluble esterase (Est-a) found only in the antennae. Est-a was known to be produced initially it the distal flagellar segments and age-related increases in concentration have been recorded in male beetles in comparison to females. The ventral surface of the 5 distal segments of male antennae possess a field of raised, smooth cuticle having pit-like depressions. The pits contain unusual cup-shaped sensilla abundantly supplied with pore tubules, typical of those associated with olfactory processes in other species. The epicuticle of the cur) sensilla is thin but lacks the pores commonly found in olfactory sensilla. The duct of at least one dermal gland opens into each pit. When sectioned antennae were stained fcr general esterase activity, it was the cells of the dermal glands that stained positive. The pit fields are unique to males. However, cup sensilla and dermal glands with esterase activity are present on female antennae and at sites outside the pit fields on male antennae. Circumstantial evidence suggests that the observed sensillum type functions in olfaction. The sensilla and associated glands in the pit fields of males may be involved in detection of the female-produced sex pheromone, 8-methyl-2-decyl propanoate.

Effects of a juvenile hormone analogue on the metamorphic changes of the foregut and midgut in Tenebrio molitor L. (Insecta, Coleoptera)

During normal Tenebrio metamorphosis, the smooth pupal foregut cuticle is replaced by a thicker adult cuticle with spines. The pupal midgut epithelium includes regenerative cells organized into nests that proliferate during pupal life, protruding as crypts into the general cavity. At high levels of treatment with juvenoid (Methoprène), some adult characteristics of the foregut cuticle were observed: the foregut cuticle apolysed soon after ecdysis, and the duration of cuticular secretion was shortened. Differentation of the pupal midgut into the adult form was either stopped or delayed by the juvenoid; the growth of the crypts was often inhibited in supernumerary pupae and in other cases could be observed 10 days later than in controls.

Studies on the host/parasite interface during the development of a pentastomid arthropod parasite in rodent intermediate hosts, with observations on protective surface membranes

The changing structure of the cuticle of the arthropod pentastomid parasite Porocephalus crotali, during growth to the infective stage in mouse and rattlesnake hosts, is described. The outermost cuticulin layer of the cuticle in instars II–VI is elevated to form a dense mat of epicuticular hairs. Since the VI larval cuticle is retained by the infective (VII) nymph as a protective sheath, effectively all stages in mice present a hairy surface to the host and this may constitute a physical barrier to inflammatory cells. The entire surface is overlain by a triple-track ‘unit’ membrane whose biophysical properties resemble those of a conventional plasma membrane, and there is evidence to suggest that this membrane is susceptible to immune attack. Under natural circumstances, epicuticular hairs entrap secretion, delivered to the cuticle via innumerable minute ducts which communicate with tegumental secretory cells termed subparietal cells (SPC). SPC synthesize lamellate droplets which unfold on the cuticle to constitute a layer of protective polymorphic vesicles. By contrast, infective nymphs in snakes possess a smooth cuticle and SPC membranous secretion is stacked over the entire surface, in sheets up to 20 deep. The function of the lipid and protein components of SPC secretion is discussed.

Pharmacognostic Studies onDatura metelLinnaeus the Anatomy of the Leaf

AbstractHistologically Datura metel L. is readily distinguished from other cogeneric drug species by its smooth cuticle, basal width of covering trichome (measuring up to 34 μ), presence of stomata on both upper and lower leaf epidermides, non-warty stalk of glandular trichomes, collapsed stomata on leaf epidermis. Figures of quantitative microscopy are reported. Histological characters used to complement morphological ones enable one to identify drug in entire or powdered form.

Rediscovery of Gracilancea Graciloides (Micoletzky, 1925) Siddiqi, 1976 (Nematoda: Tylenchida)

G. graciloides is redescribed from Karelia, USSR. It has an almost smooth cuticle, obscure lateral field and deirid, no phasmids, distinct labial disc, amphidial apertures on anterior surface beyond the labial disc, spermatheca offset, crustaformeria as quadricolumella. Males are described for the first time. The relationships of Gracilancea Siddiqi, 1976 are discussed.

Ultrastructure of the larval antenna of Tenebrio molitor L. (Coleoptera: Tenebrionidae): structure of the blunt-tipped peg and papillate sensilla

Each antenna of a final instar Tenebrio molitor larva has two blunt-tipped pegs and two papillate sensilla. The former are short pegs with fluted cuticle and a terminal moulting pore and are set in deep sockets. Two large microtubule-filled dendrites fill a dense dendritic sheath within the peg; below the base of the peg they are joined by a lamellate dendrite and a dendrite resembling a scolopidial cilium. There are four accessory cells, the innermost resembling a scolopale cell. This sensillum may be thermo- and hygro-receptive.Superficially the papillate sensillum is radially symmetrical with a central zone of small cuticular papillae surrounded by one or two rings of smooth cuticle. Three or four dendrites (of five) end under a turret of longer papillae at the center of the papillate cuticle. Fine pores from the dendritic canal extend to the surface between the papillae. One or two dendrites, one of which may be lamellate, end well below the end organ. There are five accessory cells. The sensillar and ciliary sinuses are large and the bounding membranes of the sheath cells highly elaborated. The function of this sensillum is uncertain.