206 REPORT OF STATE GEOLOGIST. 



In feeding, they eat the edges of a leaf, preferably those of an 

 oak or wild cherry, usually straddling it with their legs, and in an 

 hour will devour a piece an inch long by a third of an inch wide. 

 Kilcy records that on occasions they are so numerous as to do much 

 damage to oak, hickory, locust and other trees. In Yates County, 

 New York, in 1878, Dr. Riley found them very abundant in a wood- 

 land of 50 acres, which they had attacked in numbers two and four 

 years previously. He states that: "By the middle of August the 

 bulk of the pests were going through their last moult, and by the end 

 of autumn they had stripped most of the trees, showing, however, a 

 decided preference for the black, red and rock-chestnut oaks, over 

 the white oaks and hickories, which they affect but little until after 

 the first mentioned trees are stripped. The underbrush was also 

 very effectually cleaned of its foliage, and the insects hung from and 

 clung to the bare twigs and branches in great clusters. They settle 

 to roost on the witch-hazel, but do not defoliate it until the other 

 trees mentioned are pretty bare. Sumach and thorn are also little 

 affected, while peach and apple in an adjoining orchard were un- 

 touched. Whenever they have entirely stripped the trees and 

 shrubs they move in bodies to fresh pastures, crowding upon one 

 another and covering the ground, the fence rails, and everything 

 about them so that it is impossible for a person to enter the woods 

 without being covered by them. The timber affected can be recog- 

 nized by its seared and leafless appearance from a great distance, 

 and upon entering the woods the ear is greeted by a peculiar seething 

 noise, resulting from the motion of the innumerable jaws at work 

 on the leaves. Their depredations first begin to attract attention 

 soon after wheat harvest, and are most noticeable in September. The 

 injury to the trees done in 1874 and 1876 was manifest in the death 

 of most of the black oaks, and, according to the owner's observations, 

 trees die in three years after the first attack." 



The eggs, of which each female lays about 100, are a little less 

 than 3 mm. in length, long oval in shape and of a polished black color 

 with a whitish stripe on one side. They resemble a small, plump 

 bean or seed of other leguminous plant. "They are simply dropped 

 loosely upon the ground from whatever height the female may hap- 

 pen to be, and, during the latter part of autumn where the insects 

 are common, one hears a constant pattering, not unlike drops of rain, 

 which results from the abundant dropping of these eggs, which in 

 places lay so thick among and under the dead leaves that they may 

 be scraped up in great quantities. From general observations of 

 specimens kept in confinement, it would appear that each female is 



