No. 4. — 1848. J ON COLLECTING LEP1DOPTEKA. 7 



These larvas are shaped somewhat like the common " wood- 

 louse" (Oniscus) with the head and feet hidden. They spin 

 themselves little round or oblong hard cocoons, in which they 

 undergo their transformations; and the perfect fly on emerging 

 pushes open a little trap door, hitherto fastened by means of a 

 natural gum, which is now melted by a strong acid secreted by 

 the moth. All insects which spin cocoons are furnished with 

 the above Darned fluid, with the exception perhaps of some of 

 the Saturnia tribe, which do not close the ends of the cocoon^ 

 but spin thick hairs over them in the shape of an " eel pot." 



As my object in writing is the advancement of science and 

 to assist those who desire to collect for the purpose of investi- 

 gating the habits and peculiarities of insects, I would direct 

 the reader's attention to the advantage, in the rearing of larvse, 

 of ascertaining the moth or butterfly to which each belongs. 

 To effect this, several gauze cages should be made for the 

 purpose of separating the larvse. The reason of this is obvious. 

 The larvae of many Noctua descend into the earth to effect their 

 Anal change, and the pupae being of one uniform shape and 

 colour, it is impossible to distinguish between them; and if all 

 be put in the same case, they, by coming out together, make 

 " confusion worse confounded." Let each caterpillar have, if 

 possible, its own cage ; let it be numbered and sketched ; write 

 down the name of the plant on which it feeds, with the dates 

 of its entering into and emerging from the pupa state. These 

 notes will not occupy much time, and, if not valuable to the 

 observer, may, if properly and carefully kept, be of great 

 service to a scientific man. 



Butterflies and the larger moths and Sphingidce require a 

 large roomy box to expand their wings in on first emerging ; 

 they also require to creep with facility up the sides of the cage, 

 that their bodies and wings, by hanging down, may stretch and 

 harden. The very act of creeping upwards forces the fluids 

 from the body (which may be seen alternately contracting and 



