2^2 DAVENPORT ACADEMY OP SCIENCES. 



tender twigs and petioles and the different parts of the leaves at 

 times in such immense numbers as to completely deform and cause 

 them to dry up and drop to the ground, literally, at times, defoli- 

 ating the tree. My attention was first called to this particular 

 species in May, 1883, when, passing through a strip of woods bor- 

 dering the Potomac River in Virginia, I observed that the air 

 was swarming with the migratory form. The insects were set- 

 tling not only on the leaves of the different species of Hicoria, but 

 on all other kinds of trees and shrubs and even on weeds, on all of 

 which they were actively engaged in depositing their eggs ; but 

 they all originated from a tall slender tree of Hicoria tonientosa, 

 every leaf, petiole and young twig of which was affected by the 

 galls. 



By May 27th the eggs were found upon the leaves of all sorts 

 of vegetation, generally on the under side, along the midrib and 

 the larger veins, and particularly in the angles where the veins 

 ramify. Yet many were deposited indiscriminately on all parts 

 of the leaves. 



By June ist every leaf upon the gall-covered tree was beset 

 with hundreds of eggs, while numbers of winged females were 

 still actively engaged in ovipositing. 



On June 4th these were still numerous, but the earlier depos- 

 ited eggs were already hatching. A careful study of the insects 

 from these eggs proved them to be true males and females, the 

 males about 50% more numerous than the females. The male is 

 quite active, running briskly about, while the female is more slug- 

 gish and inclined to be stationary. She is about twice the size of 

 the male and contains a single large &gg. By this time large 

 numbers of the leaves affected were dropping, and the ground for 

 some distance around the tree became covered with them. No 

 winter eggs had, up to this time, been noticed and but few of the 

 sexed individuals were seen upon the branches and upon the 

 trunks. 



On June 8th the sexes were still numerous and active, the 

 males still outnumbering the females. They could not be found 

 on or under the bark of the tree anywhere within easy reach, 

 though they were abundant under the old and rotten leaves lying 



