2S4 iJAVENfORT ACADEMY OF SCtENCfeS. 



though the sculpture was still visible ; the eyes of the embryo 

 were now easily seen through the shell, and by the 12th of April 

 or coincident with the first bursting of the buds, these eggs 

 began to hatch in large numbers, the young stem-mothers running 

 briskly in search of a suitable position to settle down and to found 

 the colonies. 



By the 15th of April most of the eggs had hatched. By the 

 28th of April most of the young stem-mothers had settled either 

 on the young petiole or mid-rib, on the cross-rib, or on the more 

 fleshy parts of the young leaves, where small depressions or cav- 

 ities had been formed. 



By May 8th it was noticed that the galls had been formed on 

 almost all parts of the leaves or on the petioles or on the more 

 tender twigs. The more perfect specimens were growing singly, 

 resembling a blunt tooth or thorn, those on the leaves projecting 

 about evenly on both sides though ordinarily more prominently 

 on the under side. The stem-mother had already by this time 

 acquired full growth and began depositing numerous eggs, cov- 

 ering almost the whole inner surface of the gall, the eggs placed 

 on end and side by side reminding one in miniature of the regular 

 crystallizations in the cavities of some geode. By the iSth of 

 May the galls contained, besides the eggs,. both larvae and pupge in 

 different stages of development. By the 25th the winged insects 

 had formed and were leaving the galls in large numbers and set- 

 tling, as at the same time the previous year, on all kinds of veg-. 

 etation in the neighborhood of the tree on which they had devel- 

 oped. 



To sum up the life-history of this species, the winter or im- 

 pregnated eggs are deposited early in June in all sorts of shel- 

 tered positions, especially on the upper portions of the tree ; they 

 hatch early in April of the following year, remaining dormant 

 some ten months. The stem-mother attains maturity and begins 

 ovipositing in about twenty days after hatching, while the 

 winged migratory females (sexuparse) mature and begin to leave 

 their galls in about twenty days after the first eggs are laid. The 

 first sexual individuals appear about ten days subsequently and 

 some ten days further elapse before the true female, after pairing, 

 begins to consign her single egg to its winter quarters. 



