60 



species of bombyces for the sake of their cocoons, from which they 

 obtained a threadhke substance, which we now know by the name 

 of silk, and which they wove into a material that they used for 

 clothing. This silk in one form or another enters largely into all, 

 or nearly all, pupal habitations. It may be applied in the form of 

 a fine thread, produced in orderly fashion as in the case of the " silk- 

 producing " bombyces, or as a mere gelatinous mass used to stick 

 together particles of various substances in the construction of the 

 habitation or cocoon in which the pupa is enclosed. It is secreted 

 by the insect during its larval existence from the substances on 

 which it has fed.- 



Aristotle, who wrote more than two thousand years ago, paid 

 some little attention to the metamorphoses of insects, in the course 

 of which he mentions at least three lepidopterons, two of them being 

 probably I'ien's brassicir and Abraxas [/rossalariata, whilst the third 

 is evidently one of the larger silk-producing bombyces, whose 

 cocoon appears to have specially attracted his attention, for of it he 

 says, " From one particular large grub, which has as it were horns, 

 and in other respects differs from the grubs in general, there comes 

 by a metamorphosis of the grub, first a caterpillar, then the cocoon, 

 then the neci/dalns ; and the creature passes through all these trans- 

 formations within six months. A class of women unwind and reel 

 o'^- the cocoons of these creatures, and afterwards weave a fabric 

 with the threads thus unwound."-' 



vJoraing now to more recent times, the writers of the eighteenth 

 century paid a great deal of attention to the cocoons of the Lepi- 

 doptera and the methods of their construction. Thus, Reaumur 

 (1734) gives wood-cut figures of many of them; his delightful, if 

 somewhat verbose description of the manner in which Hi/lophila 

 bicolorana {ijiiercana), constructs its cocoon^ (for although the species 

 is unnamed the description is such as to leave no question as to its 

 identity) is worthy of closer attention by present-day entomologists 

 than we are perhaps generally inclined to give to these older writings. 

 RoseP (1746) figures the cocoons of practically all the species that 

 he describes that make them, while their representations on the 

 delightful plates in Sepp'' (1762) are as carefully delineated as are 

 those of the imago and larva ; and both authors give frequent 

 references to them in the text, evidently attaching importance to 

 the methods of preparation employed by the various species. 



In the examples of pupal habitations that I am about to show in 



- It is now common knowledge that a similar substance, known as arti- 

 ficial silk, may be produced by a chemical process from vegetable substances, 

 without the intervention of the insect. 



■^ Aristotle. Historia Animalium. Book v. 19, 551b. See D'Arcy Went- 

 worth Thompson's Translation. Vol. iv. 



* Reaumur. Memoires pour servir a L' Histoire des Insectes. Tome 1, 

 p. 559, pi. 39, figs. 8-14. 



^ Eosel V. Rosenhof. Insekten — Belustigungen. 



•" Sepp. Nederlandsche Insecten. 



