ORDER LEPIDOPTERA 49 



long, highly chitinized pieces, the members of the inner pair of 

 which fuse at the distal ends and form a somewhat bell-shaped 

 object with a sharp projecting point on the outer end (fig. 20). 

 With her body as a fulcrum she bores a tiny circular hole through 

 the epidermis and forms a pear-shaped pocket in the tissues. 

 In the larger end of this she places the egg (fig. 21). Many eggs 

 are deposited in a single leaf, often in chain-like rows of from three 

 to six or even more. The tiny scars are conspicuous from the 

 under sides of the leaves, and give a yellowish stippled effect from 

 the upper sides. Egg deposition extends over a period of several 

 days. 



The egg is soft, white, and elliptical, and measures about 0.45 

 mm. in length, and 0.34 mm. in width, and 0.24 mm. in thick- 

 ness. It is very soft, almost jelly-like, and not easy to dissect 

 out. It probably hatches in about a week. 



The eggs of Nepticula, Lithocolletis and many others that 

 are placed on the surface of the leaf are domed above and 

 flat on the side toward the leaf. From the traced impression 

 on the egg surface of the tiny veins on which they lie, one 

 may gather that the shells are soft and plastic at the time of 

 laying. 



There is great variation also in the position of the eggs 

 on the host plants. Of the upper or lower leaf sides some 

 persistently choose one and some the other surface and may 

 even more particularly limit the position to near or away 

 from the midrib or margin. Thus J. H. Wood writing of 

 British Nepticulae says that of the forty-one species whose 

 egg-laying habits were known to him, only four were in- 

 constant in their choice. Of those four one frequenting two 

 host plants placed her eggs on the upper side of the leaves 

 of one and on the underside of the leaves of the other, 

 seemingly on account of the character of the surfaces. Of 

 this discrimination he says 



Very commonly .... no explanation for the placing of the 

 eggs is possible, beyond the simple statement that it is the nature 



