Immature Instars Research Articles

Extracellular symbiont colonizes insect during embryo development.

Insects typically acquire their beneficial microbes early in development. Endosymbionts housed intracellularly are commonly integrated during oogenesis or embryogenesis, whereas extracellular microbes are only known to be acquired after hatching by immature instars such as larvae or nymphs. Here, however, we report on an extracellular symbiont that colonizes its host during embryo development. Tortoise beetles (Chrysomelidae: Cassidinae) host their digestive bacterial symbiont Stammera extracellularly within foregut symbiotic organs and in ovary-associated glands to ensure its vertical transmission. We outline the initial stages of symbiont colonization and observe that although the foregut symbiotic organs develop 3 days prior to larval emergence, they remain empty until the final 24h of embryo development. Infection by Stammera occurs during that timeframe and prior to hatching. By experimentally manipulating symbiont availability to embryos in the egg, we describe a 12-h developmental window governing colonization by Stammera. Symbiotic organs form normally in aposymbiotic larvae, demonstrating that these Stammera-bearing structures develop autonomously. In adults, the foregut symbiotic organs are already colonized following metamorphosis and host a stable Stammera population to facilitate folivory. The ovary-associated glands, however, initially lack Stammera. Symbiont abundance subsequently increases within these transmission organs, thereby ensuring sufficient titers at the onset of oviposition ~29days following metamorphosis. Collectively, our findings reveal that Stammera colonization precedes larval emergence, where its proliferation is eventually decoupled in adult beetles to match the nutritional and reproductive requirements of its host.

Differential gene expression of Asian citrus psyllids infected with 'Ca. Liberibacter asiaticus' reveals hyper-susceptibility to invasion by instar fourth-fifth and teneral adult stages.

The bacterial pathogen Candidatus Liberibacter asiaticus (CLas) is the causal agent of citrus greening disease. This unusual plant pathogenic bacterium also infects its psyllid host, the Asian citrus psyllid (ACP). To investigate gene expression profiles with a focus on genes involved in infection and circulation within the psyllid host of CLas, RNA-seq libraries were constructed from CLas-infected and CLas-free ACP representing the five different developmental stages, namely, nymphal instars 1-2, 3, and 4-5, and teneral and mature adults. The Gbp paired-end reads (296) representing the transcriptional landscape of ACP across all life stages and the official gene set (OGSv3) were annotated based on the chromosomal-length v3 reference genome and used for de novo transcript discovery resulting in 25,410 genes with 124,177 isoforms. Differential expression analysis across all ACP developmental stages revealed instar-specific responses to CLas infection, with greater overall responses by nymphal instars, compared to mature adults. More genes were over-or under-expressed in the 4-5th nymphal instars and young (teneral) adults than in instars 1-3, or mature adults, indicating that late immature instars and young maturing adults were highly responsive to CLas infection. Genes identified with potential for direct or indirect involvement in the ACP-CLas circulative, propagative transmission pathway were predominantly responsive during early invasion and infection processes and included canonical cytoskeletal remodeling and endo-exocytosis pathway genes. Genes with predicted functions in defense, development, and immunity exhibited the greatest responsiveness to CLas infection. These results shed new light on ACP-CLas interactions essential for pathogenesis of the psyllid host, some that share striking similarities with effector protein-animal host mechanisms reported for other culturable and/or fastidious bacterial- or viral- host pathosystems.

New genera and species of felt scales (Hemiptera: Coccomorpha: Eriococcidae), with descriptions of new species and immature instars of described species

In this work, emphasis is placed on the Eriococcidae (Hemiptera: Coccomorpha) of the Nearctic Region including the immature instars of many species not previously described, two new genera (Carphococcus Miller and Stocks and Ypofloiococcus Miller and Stocks), and 11 new species (Acanthococcus pennyae Miller and Stocks, Carph. apodus Miller and Stocks, Carpochloroides eugeniae Miller and Stocks, Ovaticoccus betsyae Miller and Stocks, Ov. gordoni Miller and Stocks, Ov. haigi Miller and Stocks, Ov. maryfoleybensonae Miller and Stocks, Ov. telotrichus Miller and Stocks, Ov. tuttlei Miller and Stocks, Ov. villanuevorum Miller and Stocks and Y. libeauae Miller and Stocks). In addition to the new taxa, descriptions and illustrations are provided for adult females, adult males and/or immature instars of Ac. arenosus (Cockerell), Ac. coccineus (Cockerell), Ac. dennoi Miller and Miller, Ac. gallicolus (Cockerell & Rohwer), Ac. hoyi Miller and Miller, Ac. kemptoni (Parrott), Apezococcus idiastes Ferris, Carpo. mexicanus Ferris, Cryptococcus fagisuga Lindinger, Cr. williamsi Kosztarab and Hale, Hypericicoccus hyperici (Ferris), Ov. agavacearum Pellizzari and Kozár, Ov. agavium (Douglas), Ov. cornutus (Ferris), Ov. densus (Miller), Ov. eriogoni (Miller), Ov. exoticus Pellizzari and Kozár, Ov. neglectus (Cockerell), Ov. peruvianus (Granara de Willink & Díaz), Ov. salviae Miller, Ov. sanguineus (Miller), Ov. tippinsi Miller and Miller, Ov. variabilis Miller, Spiroporococcus braggi (Cockerell & Robinson), S. yuccae (Ferris) and Xerococcus foquieriae Ferris. Lectotype designations are made for Ap. idiastes. Carpo, mexicanus and H. hyperici. New collection data are provided for Ov. californicus McKenzie, Ov. johnsoni (Miller), Ov. mackenziei Miller, Ov. parvispina (Chaffin) and Ov. viscosa (Kondo). Dichotomous keys are given for: determination of most eriococcid instars of both sexes; Nearctic genera of the Eriococcidae based on adult females; adult females, second-instar females, second-instar males, and first-instar nymphs of Ovaticoccus Kloet 1944; and the seven species of Acanthococcus Signoret 1875 treated here, based on first-instar nymphs. Oregmopyga Hoy 1963 and Cornoculus Ferris 1955 are treated as junior subjective synonyms of Ovaticoccus. Atriplicia Cockerell and Rohwer 1909 has been placed previously as a junior synonym of Eriococcus but here is regarded as a junior subjective synonym of Acanthococcus. We treat 44 species; new descriptions are provided for 101 treated instars, and detailed line drawings are given for all but three of them. The following species, listed in ScaleNet as occurring in the Nearctic Region, are transferred to Acanthococcus from Eriococcus Targioni Tozzetti 1868: Acanthococcus actius Miller and Miller 1993 rev. comb.; Ac. arenariae Miller and Miller 1993 rev. comb.; Ac. barri Miller 1991 rev. comb.; Ac. beshearae Miller and Miller 1993 rev. comb.; Ac. dennoi Miller and Miller 1993 rev. comb.; Ac. droserae Miller, Liu and Howell 1992 rev. comb.; Ac. epacrotrichus Miller and Miller 1992 rev. comb.; Ac. froebeae Miller 1991 rev. comb.; Ac. gallicolus (Cockerell & Rohwer 1909) comb. n.; Ac. hoyi Miller and Miller 1992 rev. comb.; Ac. mackenziei Miller and Miller 1992 rev. comb.; Ac. macrobactrus Miller and Miller 1992 rev. comb.; Ac. megaporus Miller and Miller 1993 rev. comb.; A. mesotrichus Miller and Miller 1993 rev. comb.; Ac. microtrichus Miller and Miller 1992 rev. comb.; Ac. monotrichus Miller and Miller 1993 rev. comb.; Ac. ophius Miller and Miller 1993 rev. comb.; Ac. stauroporus Miller and Miller 1992 rev. comb.; Ac. washingtonensis Miller and Miller 1992 rev. comb.; and Ac. whiteheadi Miller 1991 rev. comb. In addition, two species are transferred to Acanthococcus from Rhizococcus Signoret: Ac. coccineus (Cockerell 1894a) rev. comb. and Ac. kemptoni (Parrott 1900) rev. comb. Three images of water color paintings by Mary Foley Benson are included.

Morphological description of ontogenetic stages in Parasitus yuensis Ma & Lin (Acari: Parasitiformes: Parasitidae)

The study presents a detailed description of all instars of Parasitus yuensis Ma & Lin, based on collected specimens from haystack, rotten leaves or the body surface of millipedes, and on laboratory reared specimens. The female is redescribed, male and immature instars are described for the first time.

A new coccoid family (Hemiptera: Coccomorpha) for an unusual species of scale insect on Podocarpus macrophyllus (Podocarpaceae) from southern China.

A new family, Qinococcidae Wu, fam. n., is established for the species Qinococcus podocarpus gen. n. and sp. n., collected from southern China under the bark of Podocarpus macrophyllus (Podocarpaceae). The adult female and male, egg, and all immature instars including the male pupa of Q. podocarpus sp. n. are described and illustrated. The new family is diagnosed mainly on the adult male possessing an inverted -like post-tergite and unusual venation of the fore wing, with a pterostigma, posterior cubital vein and bifurcate anterior flexing patch. A key to all the developmental stages is provided.

Knockdown of ecdysteroid synthesis genes results in impaired molting and high mortality in Bactericera cockerelli (Hemiptera: Triozidae).

RNA-mediated interference (RNAi) has become a promising biopesticide technology with which to direct sequence-specific gene knockdown of key targets in the potato psyllid (PoP) Bactericera cockerelli, resulting in significant mortality. In this study, three strategically selected target genes, ATF4, C7 and D24, essential for the biosynthesis and regulation of ecdysteroids, were evaluated for knockdown and mortality using oral delivery of individual, paired and all three double-stranded RNAs (dsRNAs), in five replicated experiments. Knockdown was determined as the fold-change in gene expression using a quantitative polymerase chain reaction. Knockdown of the D24 target, at 39%-45%, resulted in 51% PoP mortality by 10 days post-ingestion (dpi) of dsRNA. Knockdown of C7, at 38%-61%, resulted in 53% mortality by 10dpi, whereas dsD24 ingestion resulted in 65% mortality by 10dpi when dsD24 and dsC7 were co-delivered. Three phenotypes, INCOMEC, PREMEC and SWOLLEN, were observed at a frequency of 4%-12%, and are consistent with incomplete ecdysis in immature and/or adult PoP. Adult PoP exhibiting INCOMEC survived for several days but were unable to mate or fly, whereas SWOLLEN and PREMEC were lethal to the immature instars. Knockdown of ATF4 did not result in the mortality or malformations in immature and adult PoP. Compared with knockdown of individual D24 and C7 targets, significantly greater RNAi penetrance was achieved following delivery of combined dsRNAs. The highest knockdown that resulted in incomplete ecdysis and/or mortality was obtained for targets with predicted involvement in the same or interacting pathway(s). Knockdown of ATF4 was apparently "rescued" by uncharacterized compensatory gene(s) or effects. © 2022 Society of Chemical Industry.

The Wheel Bug Arilus gallus (Hemiptera: Reduviidae): Life History and Description of Immature Stages

The wheel bug Arilus gallus Stål (Hemiptera: Reduviidae) is a native American assassin bug that has been recorded preying on insect pests of coffee in Colombia. To provide information to support conservation biological control using this species, life-history parameters for A. gallus were investigated. Arilus gallus was reared under laboratory conditions at Cenicafe, on Galleria mellonella Linnaeus (Lepidoptera: Pyralidae) as prey. All immature stages are described and illustrated for the first time. To obtain fecundity parameters, we used 1,818 eggs of the first generation (F1) oviposited from 19 pairs of adults. The mean number of eggs per female was 182.53 ± 7.15, derived from a mean of 1.68 egg masses per female. The egg incubation period was 27.52 ± 1.15 days; egg hatch rate was 80.66%; mean duration from egg to adult was 112.46 ± 5.5 days; and rate of survival to the adult stage was 9.69%. The longevity of adults was 109.66 ± 10.41 days for females and 89.4 ± 8.74 for males. The five immature instars can be distinguished by differences in several anatomical features, including the progressive increase in body size and the color of the abdomen and legs.

Pre-oviposition Period and Immature Development of Maconellicoccus hirsutus (Hemiptera: Pseudococcidae) on Cucurbita moschata 'Black Futsu' Squash.

The developmental time of pink hibiscus mealybug, Maconellicoccus hirsutus (Green), immatures was investigated on the host plant Cucurbita moschata Duchesne ex Poiret variety 'Black Futsu.' Because host plant species influences developmental rates of M. hirsutus, understanding the life history of this specific host plant has implications for the mass rearing protocols of its natural enemy, Anagyrus callidus Triapitsyn, Andreason and Perring, currently being released in California, United States. Fruit from 'Black Futsu' squash were infested with first instar pink hibiscus mealybug and kept at 26.6 ± 2°C, 50 ± 10% RH, and 0:24 (L:D) h photoperiod for the duration of the experiment. Every 24 h the life stages of pink hibiscus mealybug individuals on the squash were recorded. After adult eclosion, observations of adult females continued until the first eggs hatched, which revealed an average pre-oviposition period of 7.2 ± 0.1 d and an average length of the egg stage of 7.0 ± 0.0 d. The average developmental times for both sexes were similar from the egg stage through the second instar. Third instar females took nearly twice as long (7.2 d) to develop into adults as did third instar males. However, females have just three immature instars while males have four. The males spent an average of 4.5 ± 0.3 d as third instars and 4.8 ± 0.4 d as fourth instars before developing into winged adults. On average, female immature developmental time was 27.8 ± 0.2 d from egg to adult and male developmental time was 29.4 ± 0.2 d from egg to adult. The implications of these results on rearing A. callidus are discussed.

Differential thermal tolerance across life stages under extreme high temperatures crossed with feeding status in corn leaf aphid

1. Climate change is expected to increase the frequency and duration of extreme heat events, which would pose significant challenges to most ectotherm species, such as insects.2. In the study, we address the thermal tolerance of corn leaf aphid, Rhopalosiphummaidis (Hemiptera: Aphididae) under brief extreme high‐temperature events (i.e. heat waves) across life stages. Immature instars and adults of R. maidis were exposed to heat events of increasing temperatures (0.5 °C min−1), starting at 22 °C and reaching one of the selected maximal temperatures (from 38.5 to 44.5 °C with an increased interval of 0.5 °C). In each temperature regime, the mortality of R. maidis was compared with and without barley seedlings.3. Results showed that the critical high temperature (CHT) of R. maidis was 39.0 °C in no feeding treatments, while it was 39.5 °C in feeding treatments. The upper lethal temperatures (ULTs) of R. maidis were significantly different between feeding and no feeding treatments. In addition, the ULTs varied significantly across life stages with the highest ULT values for 4th instars. Feeding significantly increased the thermal tolerance of phytophagous insects.4. Variable balances in plant‐herbivore interactions will be induced according to the insect feeding diet status and instar stage when experiencing extreme temperatures resulting from the warming climate. The findings will provide valuable information for understanding the role of food intake in thermal adaptation of small arthropods to extreme high‐temperature events under climate change.

Life Table and Morphometric Studies of Aulacaspis tubercularis Infesting Mango Trees in Egypt (Diaspididae: Hemiptera)

White mango scale, Aulacaspis tubercularis Newstead (Hemiptera: Diaspididae) is a serious pest on mango (Mangifera spp.), (Sapindales: Anacardiaceae) which became recently a trouble some pest in all mango orchards in Egypt. Biology of the scale insect A tubercularis (Hemiptera: Diaspididae) was studied on mango saplings (Mangifera sp.) at mean temperature of 30°C and relative humidity (RH) of 64 % at the laboratory during summer and winter seasons in Department of Agriculture Ain shams university, Government of Qalyubiya, Egypt. Observations of developmental stages and morphometry of A. tubercularis were conducted using a head lens and an ocular and stage micrometers. In the laboratory conditions, mature females laid 85-200 eggs in 10–12 days under the scale cover; the eggs hatched after 6–7 days. A. tubercularis males passed through two feeding instars then pre-pupal, pupal and adult stages while females had two immature instars with pre-oviposition, oviposition and post-oviposition periods. Mean developmental span (egg to adult) of male insect was 53.5 days and for female was 67 days. The periods of the age and survival stages were almost close to the point of congruence in some stages. Mean developmental periods on mango saplings in summer were 8, 32, 2, 4, and 2 days for stages of males and 8, 32, 10, 12 and 8 days for stages of females, respectively while in winter were 8, 30, 2, 4, and 3 days for stages of males and 8, 30, 8, 12 and 12 days for stages of females, respectively.

Descriptions of the Nymphal Instars of the Mexican Endemic Ambrysus inflatus La Rivers (Heteroptera: Nepomorpha: Naucoridae)

Of the 97 described species in the New World genus Ambrysus Stal, the nymphal instars of only one North American species have been described. This work represents the first contribution where the immature instars of a Mexican endemic species are characterized and illustrated, Ambrysus inflatus La Rivers. The descriptions are based on specimens collected in Lago de Chapala, Michoacan, in central Mexico. The main characters to distinguish among instars are related to the overall size and relative length of the mesonotal wing pad compared with the exposed part of the metanotal lateral margin. Some characteristics of the immature instars of Ambrysus inflatus and A. lunatus Usinger are briefly discussed. A comprehensive list with references of the species of Naucoridae for which some or all the immature instars have been described is presented.

Biology and Life Stages of Pine Spittle Bug Ocoaxo assimilis Walker (Hemiptera: Cercopidae)

The first records of outbreaks of the Pine Spittle bug Ocoaxo assimilis Walker were recently identified from Puebla, Mexico, which promoted more than 2600 ha of forest foliar fall. Beyond the taxonomic and distribution information of this species, the basic traits of its biology remain unknown. This study aims to describe some biological aspects of O. assimilis, in a natural pine forest at Nicolás Bravo, Puebla (NB). Using morphological characteristics and a phylogenetic analysis of a fragment of cytochrome oxidase subunit I mtDNA (COI), immature instars with adults were studied; the instar number was determined by means of a multivariate analysis of 19 morphological characteristics of 121 specimens. The systematic sampling to evaluate the occurrence of nymphal specimens during a year, plus host selection experiments, allowed for determination of the abundance over time, voltism, and host preferences. Phylogenetic analysis of the COI supported that both nymphs and adults collected in NB correspond to O. assimilis. Principal coordinate analysis supported the existence of five nymphal stages. Field sampling and host selection experiments indicated that this species displays a single generation per year, is associated with the rainy season, and that specimens from the three first nymphal stages feed on roots of eight host species (one grass, four herbaceous species, one bush, and two trees). From the fourth instar, the insects feed on pine roots to complete their development, and when they are adults, they migrate to needles of young or mature pine stands of Pinus pseudostrobus to feed and reproduce.

Evidence of acaricide resistance in different life stages of Amblyomma mixtum and Rhipicephalus microplus (Acari: Ixodidae) collected from the same farm in the state of Veracruz, Mexico

The objectives of this study were to evaluate the resistance of Amblyomma mixtum and Rhipicephalus microplus ticks from co-infested bovines from the Veracruz region in Mexico to different acaricide families and to demonstrate the viability of the packet test on different A. mixtum instars. The following acaricide families were used: a combination (cypermethrin 15 g + chlorpyrifos 25 g + citronella 1 g + butoxide piperonyl 15 g), amidine (formamidine 12.5 g), pyrethroid (cypermethrin 15 g), and organophosphate (dichlorvos 60 g + chlorpyrifos 20 g). Regarding the packet test in both species, resistance was found for the pyrethroid and amidine families in A. mixtum and R. microplus, as efficacy did not surpass 40 %, including in immature instars; regarding the adult immersion test in R. microplus, the efficacy was 93.3 % for the amidine family and 26.2 % for the pyrethroid family. The proposed methodology is an alternative technique to optimize resistance detection in immature ticks with a heteroxenous life cycle.

Drywood Pest Termite Cryptotermes brevis (Blattaria: Isoptera: Kalotermitidae): a Detailed Morphological Study of Pseudergates.

The Kalotermitidae Cryptotermes brevis (Walker) presents colonies that lack a true worker caste. They have totipotent worker-like individuals named pseudergates. Few studies have characterized the morphology of immature instars, including pseudergates. In order to identify these instars and characterize the pseudergates, we conducted a comparison between morphometric and morphological variations among immature individuals of C. brevis colonies. Juvenile hormone analog (JHA) was used in the first instar nymphs to induce regressive molts and compare morphological differences between nymphs and pseudergates. Results showed the existence of three larval instars and four nymphal instars. These immatures were morphologically characterized. Individuals classified as third instar larvae presented white body, 10 to 12 antennal articles, absent or small non-pigmented compound eyes, and absence of wing buds. Pseudergates presented pigmented abdomen and sclerotized cuticle, 10 to 12 antennal articles, and absent or small compound eyes, and few specimens had large pigmented compound eyes and absence of wing buds. First instar nymphs had pigmented abdomen and sclerotized cuticle, 10 to 12 antennal articles, both large non-pigmented and pigmented compound eyes, the presence of wing buds. Bioassays using JHA on first instar nymphs resulted in a large percentage of nymph-soldier intercastes. We concluded that abdomen pigmentation and sclerotized cuticle are good characters to differentiate pseudergates from larvae and the absence of wing buds is a good character to differentiate pseudergates from nymphs. Our findings not only contribute to the basic biological and morphological information of this species but also help to identify correctly pseudergates in further studies that involve applied bioassays.

Accelerating studies on the ontogeny and morphological diversity in immature mites.

Over 58,000 species of mites have been described (Zhang 2011; Liu et al. 2013). Most species of mites are known only as adults, although immature instars also present a diversity of characters and other information potentially useful for understanding mite taxonomy, phylogeny and biology. A recent overview of juvenile instars of oribatid mites (excluding Astigmata) shows that only about 8% of the known oribatid mites have one or more juvenile instars described (Norton Ermilov 2014). A survey of papers published during the last three years (2015-2017) in five main acarological journals (Acarina, Acarologia, International Journal of Acarology, Persian Journal of Acarology, Systematic and Applied Acarology) and two other main zoological journals (Zootaxa and ZooKeys) with mite papersshowed only 3% to 19% of these with descriptions of immatures, but among the 151 species included in these papers as many as 61% have full data on the ontogeny (Liu Zhang 2018).

Philippinozercon, a new genus of Heterozerconidae (Parasitiformes: Mesostigmata), with description of all active instars.

The generic classification of millipede associated Heterozerconidae in the Oriental region is revised. The genus Allozercon Vitzthum is re-diagnosed and Asioheterozercon Fain is designated as an subjective junior synonym of Allozercon. Philippinozercon gen. nov., with the type species P. makilingensis sp. nov., is described for all instars. This genus may be endemic for the Philippines, but is quite widespread in that country. All immature instars are described, making this the second species of Heterozerconidae known for all instars. The morphology of the immatures is compared with that of immatures of the temperate species Narceoheterozercon ohioensis and unnamed species from Brazil and Thailand. All immatures were collected from millipede frass and litter, never from millipedes. Adults are associated with millipedes in the family Trigoniulidae (Spirobolida).

A survey of descriptions of immature instars of mites during the last three years.

Immature instars of mites can provide valuable information for understanding mite taxonomy and evolution. However, most taxonomists described only adults and rarely did they also describe immature stages and the ontogenetic sequence. For example, only about 8% of the known oribatid mites (excluding Astigmata) have one or more juvenile instars described (Norton Ermilov 2014). Since then we noted rapid increase of papers on the ontogeny of oribatid mites as well as other mites in Systematic and Applied Acarology during our editing and production process. The purpose of this paper is to provide a survey of descriptions of immature instars of mites during the last three years (2015-2017). We follow our previous methods in sampling most important journals in mite systematics (Liu et al. 2013; Liu Zhang 2016; Li Zhang 2016; Wei Zhang 2016; Liu et al. 2017), while expanding the scope further to include more journals that publish a significant amount of mite taxonomic papers.

Ontogenetic development and redescription of Oligonychus pratensis (Banks, 1912) (Acari: Tetranychidae).

Oligonychus pratensis (Banks, 1912) is redescribed based on adult females as well as immature instars collected from Imperata (Poaceae) in Zhangjiajie City, Hunan Province, China. The ontogenetic development of chaetotaxy in O. pratensis is the same as that in O. afrasiaticus (McGregor, 1939) and O. saccharinus Baker Pritchard, 1960. Moreover, we remove O. shinkajii Ehara, 1963 from synonymy with O. modestus (Banks, 1900), due to significant differences in their aedeagal morphology.

Ontogeny of morphological traits in Eupelops variatus (Mihelčič, 1957), with remarks on juveniles of Phenopelopidae (Acari: Oribatida)

Juvenile instars of oribatid mites of the family Phenopelopidae are well known compared to most other families, however, information on the morphological ontogeny of the majority of species is still insufficient or unknown. Comparative characteristics of immatures of species of Phenopelopidae are given based on our own data and available literature sources. The major characteristics of immature instars of 11 species are presented, and the morphological ontogeny of Eupelops variatus (Mihelčič, 1957) is investigated based on material from southern Europe. From these studies, it can be generalized that the juvenile morphologies of phenopelopid genera are quite similar and uniform. The juveniles have plicate integument, marginally flattened opisthonotum, and short gastronotic setae c1, c3 and of the d-series. The juveniles of the phenopelopid species differ from one another in morphological characters such as body size, development of the prodorsal ridges, lamellar, interlamellar as well as gastronotic setae of c2, lp and h-series either in larva or nymphs, and all these characters have species-specific value.

Mosquitoes (Diptera: Culicidae) of the meridian zone of the subtropical mountainous rainforest of Argentina: update on the fauna and geographical distribution

We report here three new mosquito records in the Yungas ecoregion [Culex (Culex) dolosus, Culex (Micro­culex) Pleuristriatus Series and Howardina sp.] and the expansion of the distributions of 17 species of the genera Anopheles, Culex, Aedes, Psorophora, and Toxorhynchites for Argentina. These findings broaden the total number of species recorded for northwestern Argentina to 174, from which number 57 species are distributed in the Tucumán province, 21 in the Catamarca, and 96 in the Salta. Also included is information on immature instars collected in phytotelmata.