New York Agricultural Experiment Station. 351 



tinue to grow, evidently by the absorption of moisture from the 

 leaf tissue, until fully developed. As the egg increases in size the 

 tissue about it gradually turns lighter in color, finally becoming 

 yellow. Thus, as previously stated, the infested leaves soon be- 

 come spotted on the upper surface. (Plate XXVI, Fig. 4.) 



The egg when first removed from the body of the female has. 

 been described by Saunders 5 as approaching a " long oval in form,, 

 rather obtuse at the ends and attaining its greatest diameter a 

 little before the middle. Color white, with a faint yellow tinge 

 and a smooth, glossy surface, semi-transparent." 



The fully developed egg, as it appears when removed from the 

 leaf, is white or slightly tinged with yellow and nearly pear-shaped.. 

 The average measurement is 1.2 mm. by 0.6 mm. at the widest 

 point. As with the newly deposited egg the enveloping mem- 

 brane is smooth and semi-transparent, plainly showing the move- 

 ments of the embryo within. The number of eggs deposited on a. 

 single leaflet may reach as high as 24. 



Period of incubation. — The period of incubation may vary 

 from 7 to about 10 days. Some of the specimens under observa- 

 tion hatched in about 7 days, but most of them were 10 or 11 days 

 old before hatching. The eggs from which the larva? have escaped 

 are plainly indicated by the irregular hole in. the side of the 

 swelling. 



The larva. — The larva? measure, soon after hatching, 2 mm. 

 to 2.3 mm. on an average in length. The body is nearly cylin- 

 drical, yellowish white or very pale yellowish green and well cov- 

 ered with spine-bearing tubercles. The spines are at first white, 

 but gradually change to dark brown. Before the first molt the 

 head is slightly darker and about one-fourth broader than the 

 body. The dark brown eye-like spots just above each antenna 

 are very conspicuous. With the increase in size and the succeed- 

 ing molts the color of the body becomes a pale green and finally a 

 decided green color; the dorsal spines turn darker brown. The 



5 Rpt. Ont. Ent. Soc, 1873, p. 11. 



