164 Annals Entomological Society of America [Vol. IX,. 



previous to the time of hatching agree quite closely with those 

 reported by Forbes ('10, p. 221). Apparently his measurements 

 were made on eggs which were well advanced in development. 

 Development. — The egg period was found to be about eleven 

 days, a result which agrees closely with that reported by 

 Forbes. When first laid, the eggs are yellowish, having about 

 the same color as the lower surface of the yellow water-lily leaf. 

 They are also slightly translucent. As development goes on 

 they become darker and proportionately more conspicuous on 

 the leaf. During the first 2-4 days following oviposition, little 

 if any change is apparent but subsequently internal differentia- 

 tion becomes noticeable. The eggs develop uniformly and 

 usually after a lapse of 3-5 days each begins to show a dark 

 band within, shaped somewhat like the letter J. The position 

 of this dark band is constant, the more curved end being in that 

 extremity of the egg remote from the margin of the hole in the 

 leaf. This band gradually becomes more conspicuous, ulti- 

 mately revealing itself as the developing body of the larva. 

 The triangular, chitinized pieces of the epicranium begin to 

 appear at the end of the fifth day and it was noted that they 

 develop in that end of the dark band nearest the margin of the 

 leaf puncture, showing that there is a definite orientation of the 

 egg and that the head of the larva develops at the less curved 

 end of the band. At the close of the eighth day, the larva is 

 quite distinct and occupies practically all of the space within 

 the egg. At the end of about ten days, the egg has lost all of 

 the original yellow appearance and the shell has become trans- 

 parent. The tiny caterpillar can be easily examined and it 

 begins to show movements within the egg. The primary regions . 

 of the body are now distinct (Fig. 4), the epicranium and the 

 tips of the mouth parts are dark brown, the fronto-clypeal and 

 the occipital regions are light yellow in appearance, and the 

 chitinized, dark brown prothoracic shield and the dark bands in 

 the regions of the intersegmental grooves are distinctly visible 

 through the egg shell. In the eggs studied in this connection, 

 the dark color appeared first in the ocelli and on the dorsal 

 margins of the intersegmental grooves, later in the head and 

 prothoracic shield. The larva is doubled upon itself with the 

 caudal end extending around and beyond the head. 



