Lac Insect Research Articles

A Practical Manual of Lac Cultivation

IN view of the importance of the lac industry to the Indian Empire, it is obviously desirable that the best practical information should be readily accessible to all who seek it. Mr. P. M. Glover, entomologist to the Indian Lac Research Institute at Ranchi, has produced an up-to-date guide to the subject, embodying the results of recent investigation carried out under the auspices of the Lac Research Institute, which will doubtlessly be welcomed by all the more progressive growers. The yield of the lac crop responds enormously to judicious inoculation and skilful cultivation, coupled with proper pruning of the host trees. Unfortunately, the lac insect itself has numerous enemies, and some of the most destructive are other insects of several kinds. The counteraction of the activities of such enemies is one of the most urgent problems that have to be faced, since they are responsible for the destruction of about sixty per cent of the crop produced in each year. These and other aspects of lac cultivation are discussed by Mr. Glover in his very practical guide to the subject.

65. On the Internal Anatomy of the Male Lac Insect, Laccifer lacca Kerr (Homoptera, Coccidze)

65. On the Internal Anatomy of the Male Lac Insect, <i>Laccifer lacca</i> Kerr (Homoptera, Coccidze)

14. On the Internal Anatomy of the Female Lac Insect, Laccifer lacca Kerr (Homoptera: Coccidæ)*

14. On the Internal Anatomy of the Female Lac Insect, <i>Laccifer lacca</i> Kerr (Homoptera: Coccidæ)*

On a Collection of Lac Insects from Northern India

The lac insects have, in recent years, been the object of extensive attention, partly on account of their economic importance, and partly on account of the biological interest that invests them. What the late Professor Lefroy had remarked about the Aphids in his “Indian Insect Life” may well have been said of these also but for the appearance of Chamberlin's Monograph (Bull. Ent. Res., xiv, 1923, pp. 147–122; xvi, 1925, pp. 31–42), which supplied a long-needed treatise on the subject. The weakness of this monograph, however, has seemed to me to be the insufficient treatment of the Indian forms, which was, evidently, due to lack of material, and it has therefore seemed desirable to undertake a study of the Indian lac insects in order to fill in the lacunae in this otherwise excellent monograph.

The first Stage Larva of Lac Insects

Imms &amp; Chatterjee in their classical study of the lac insect say : “ In the newly hatched larvae the sexes are indistinguishable by any external characters and it is not until after metamorphosis has set in that the separation into sexes becomes evident. We have examined a large number of the newly hatched larvae of Tachardia lacca and other Coccids and have been unable at this stage to find any external manifestation of the sexes.” There is not a word separating the first from the second sentence of the above statement, yet Negi, in his recent contribution on the lac insect, who also quotes Imms' &amp; Chatterjee's first sentence, erroneously credits the second part of their statement to me. Further, in my paper on lac insects there is a photographic reproduction (Pl. ix, fig. 26) of two larvae of different sexes which are only four days old. Again, figs. 17 and 18, on Plate vi, are male and female larvae, which have been only 24 hours on the tree and are for all purposes identical with crawling larvae.

Pupal Parasites of Holcocera pulverea, Meyr. (Lep.), an Enemy of the Lac Insect

Caterpillars of the moth Holcocera pulverea, Meyr., along with those of Eublemma amabilis, Moore, do great damage to lac cultivation by feeding upon the living insects. Misra* and Imms &amp; Chatterjee† have pointed out that H. pulverea may be found in even greater numbers than E. amabilis, though the predacious nature of the latter is more generally recognised. I have been able to confirm this observation with North Indian species of lac insects growing on Butea frondosa and Schleichera trijuga. However, in South India the wild species of lac, Lakshadia communis, at least in Mysore, is entirely free from the attack of H. pulverea, while Lakshadia mysorensis, the species commercially cultivated on Shorea talura, is never attacked by H. pulverea to the same extent that it is by Eublemma amabilis. With L. mysorensis this is partly due to H. pulverea being heavily parasitised. In the pupal stage this moth is attacked by the Chalcid, Eurytoma pallidiscapus, Cam. Imms &amp; Chatterjee mention that only four examples of this parasite were reared by them during the entire course of their study, indicating its rare association with North Indian species of lac insects. In Mysore it is far from being scarce, which has enabled its life-history to be traced as a pupal parasite of H. pulverea. Fig. 1, a, shows a pupa of this moth from which a female, Eurytoma pallidiscapus, was reared on 14th November 1922.

The Braconid GenusAphrastobracon, Ashm.

The genusA phrastobraconwas erected by Ashmead in 1895 to include an interesting new Braconid that was bred out from the lac insect,Tachardia albizziae, Gr., by Mr. E. E. Green, in Ceylon, and the species was namedA. flavipennis. Since then we have no further records of this insect from Ceylon or elsewhere. Even Mr. Green does not refer to it in connection with the same lac insect in his recent last volume on theCoccidaeof Ceylon, though he has made mention of another Braconid,Bracon greeni, Ashm., bred by him from the same host and described by Ashmead as the same time asA. flavipennis. However, this insect was noted by the writer of this paper some years ago in South India, and latterly during the course of his studies on the localCoccidaespecimens of this species were reared from two or three common scale-insects. It was at first thought to be a parasite on the scales and was identified by a well-known authority as a species ofMegalommum, Sz.; a record to this effect may be found in the author's “ List of Parasitic Hymenoptera of Economic Importance from South India ” published in 1921. Further studies and observations made on the bionomics of this insect in recent years revealed its true habit as a parasite, not on the scale, but on a Lepidopterous caterpillar feeding on the scale, and its correct identification was obtained after consulting two or three specialists. A brief reference to the insect, explaining its habits, is made in the author's recently published memoir on the nim mealy scale,Pulvinaria maxima, Gr.

The Wax Secreting Glands of Pseudococcus Citri Risso.

Wax secreting glands are found in a large number of insects scattered throughout the various orders. Though the secreted product varies greatly in composition and the uses very diverse yet, so far as known, all wax glands are epidermal in origin and usually more or less closely connected with the exterior. The most noted groups of wax producing insects are the Aphididae and Coccidae. So important is it in some of the Coccidae that very large industries are based upon the product—i. e., lac produced by the lac insects ( Tachardia lacca, Gascardia (Ceroplastes) madagascarensis , etc.). Lac is a resinous product which in the case of the Gascardia product consists of about 28.5% wax and 52.5% resin, while the lac of Tachardia lacca contains 68% resin and only 6% wax. The animal value of the Indian product now exceeds 20,000,000 and a great deal of experimental work is being done in the cultivation and improvement of the lac industry in India.

The Lac and Shellac Industry in India1

AT the present time India holds what is virtually a monopoly of lac production, and no satisfactory substitute has yet appeared on the world's markets. This monopoly cannot, however, be regarded as a sinecure; other countries are likely to be found suitable for lac cultivation, and the present high value of lac and its importance to many Western industries render it urgent that the production of this substance should be encouraged along improved scientific and economic lines. The propagation of lac is still very carelessly carried out, and its methods of collection need much improvement. The crop varies from year to year, prices fluctuate seasonally, and there is much injurious market speculation. The bulk of the world's lac comes from Chota Nagpur, Orissa, the north-eastern half of the Central Provinces, some western districts of Bengal, and from part of the Mirzapur district of the United Provinces. Out of the ninety or more trees which have been recorded as hosts for the lac insect (Tachardia lacca), the most important include Schleicheria trijuga, Butea frondosa, Zizyphus jujuba and xylopyrus, together with species of Acacia, Ficus, etc. These plants contain much gummy or resinous matter or are rich in latex.