INSTRUCTIONS FOR COLLECTING INSECTS. 191 



dition throngliout the winter, emerging as imago during the succeeding 

 spring. The observer should therefore begin his search for young 

 larvae and eggs with the first appearance of vegetation, and either 

 make them captives or mark the places where they may be found ; but 

 in general the former is preferable. Feeding and rearing larvae in 

 spring time has also this advantage : that the food-plant is kept fresh 

 longer and with less difficulty than in the latter part of summer and 

 the autumn, and specimens of the perfect insects are obtained the same 

 season. 



After the insect has changed to the pupa it should not be unneces- 

 sarily disturbed, and never handled with the fingers, except when it 

 cannot be avoided, and then the utmost gentleness of pressure should 

 be used. This applies more particular]}'- to pupa which have been 

 developed in the atmosphere of the vivarium, where its humidity pre- 

 vents the hardening of the pupa case as completely and rapidly as it 

 takes place in the external air. When it is removed from the viva- 

 rium it should be placed as nearly as possible in the same condition 

 that the larva chose for it, and the new vessel containing it should be 

 designated by the number of its caterpillar, so that the perfect insect 

 may be referred properly to its larva. The observer need not be soli- 

 citous about the apparent impossibility of the perfect insect making its 

 escape from very dense cocoons, and attempt to aid them by opening 

 them ; nature has provided a very efficient and powerful means to 

 effect what is at first view, and what naturalists themselves have re- 

 garded, a most curious puzzle. Without entering into particulars, I 

 may say here that the effective and only agent by which this is ac- 

 complished is the action of the powerful thoracic m'dscles. The larvae 

 of the fall months should not be disturbed after entering the ground, 

 for many of them hyhernoie until spring in their cells or cocoons made 

 on the surface when they change to pupae. 



The pupae of cochliopodiform or onisciform larvae are always enclosed 

 in a small ovoid, brittle, silky cocoon, and are difficult to bring to 

 maturity. The larvae hybernate in them until the following spring, 

 when they change into pupae covered by a very thin and delicate pupae 

 case. Their cocoons should be permitted to remain amongst the moss 

 where they are usually woven, and the moss should be kept moist and 

 exposed to the external air beneath some convenient and protecting 

 shelter, and covered with a layer of fine, dried grass during winter. 

 I have found a great number of very remarkable forms belonging to 

 this family, but as it was during the period of my own inexperience 

 in rearing larvae, and being unable to obtain hints from others or from 

 books, for there are none 1 believe in which the subject is treated, I 

 lost the greater portion of them and have since looked vainly for other 

 specimens. 



The vessel containing pupae should always be provided with ob- 

 jects, such as portions of the branch of a tree, fixed in the ground, in 

 order that the imago when it appears may ascend one of them and 

 expand its wings. For when they first appear their wings are unde- 

 veloped, flaccid and moist; they immediately ascend tlie first encoun- 

 tered object that is perpendicular or nearly so, and seek to place them- 

 selves in such a position that their wings may be depenclent or hang 

 downivards from the bach. Then they begin to grow and develop 



