LEPIDOPTERA. 243 



etc., be provided for such Noctuid larvte as naturally lie con- 

 cealed, such as Orthosia.) Xanthia., Noctua, etc., "•while lor 

 Agrotis and a few others a considerable depth of fine earth or 

 sand is necessary." 



"■Larv;i?, which in nature hibernate, must either be stimulated 

 by warmth and fresh food to feed up nnnaturally fast, or else 

 through the winter must be exposed to out-door temperature.' 

 For such larvjfi as begin to eat before the trees are leaved 

 out, the leaves of evergreens must be provided, pine leaves, 

 chickweed, grasses and mosses. Hibernating, living larvse, 

 must during the Avinter be kept dry, otherwise the damp seems 

 to hang about their fur, and causes them to be attacked l)y ?- 

 white fungus ; while smooth larvae require the natural damj)- 

 ness of the soil. Mr. Gibson strongly recommends that during 

 the winter all cages containing larvjB be placed in front of a 

 window facing the east or north-east, so that tlie inmates may 

 be kept as cool as possible. 



When the moth is fairly out of the pupa, as remarked hy Mr. 

 Sanborn, their wings often fail to properlj^ expand, on account 

 of the want of moisture, "the insect being unable to expand its 

 wings in a heated, dry room. He has avoided this difficulty 

 by placing the insect just emerged, or about to come foi'th, 

 beneath a bell-glass, within which he had placed moistened 

 pieces of bibulous paper." 



Mr. Trouvelot has ncjticed that the difference in size of the 

 Avings of moths or butterflies is due to the fact that some of 

 the fluid thrown into the wings diu'ing their development 

 escapes from a break in the surface of the wing, so that this 

 wing is smaller than the other. He has, by pinching a Aving 

 while thus dcA'eloping, caused the fluid to "flow from the punc- 

 ture, and immediately the Aving so wounded ceased to grow, 

 Avhile the three others continued their development to its ful! 

 extent." "I have sometimes advanced the deA'elopment of tht 

 wings of Telea Polyphemxis. I selected for this purpose, 

 pupae A'ery far advanced in their transformation, as is slioAvn by 

 the looseness of the pupal skin, and b}^ the color of the Avings 

 of the moth, which can be seen through it. I took carefully 

 the pupal skin from around the moth and suspended the insect 

 , in the position that Lepidoptera take when emei-ging from the 



