524 SEVENTH REPORT OF THE FOREST, FISH AND GAME COMMISSION. 



Insects InjQrioQS to Oal^s. 



The different varieties of oaks growing within our State afford sustenance to 

 large numbers of insects. It is impossible in the present article to even mention all 

 the species which might be met with, and only a ver\^ few of the more important 

 or the more interesting, which have come under the writer's observation in recent 

 years, are treated of briefly. 



SPECIES AFFECTING THE LEAVES. 



YELLOW STRIPED OAK CATERPILLAR. 



Anisota scnatoria Abb. & .Sm. 



A black spiny caterpillar with four orange-yellow stripes on the back and two on 

 each side, is frequently very abundant on the scrub oaks at Karner, where it annu- 

 ally defoliates manj' of these trees. It happens that the species of oak involved 

 in this attack are not of much importance, but this insect also depredates on others 

 which have a high commercial value. There are several records of this caterpillar 

 being so numerous as to migrate in swarms on railroad tracks and stop trains. The 

 economic importance of this species may be judged b\' the opinion of Dr. Packard, 

 who states that this insect and the forest tent caterpillar " as a rule do more harm 

 to, oak forests than perhaps all otlier species combined." 



Life History. The life history of this insect is substantial!}- as follows: The 

 moths appear in the latitude of New York about the .second week in June and their 

 eggs are placed in Itirge irregular clusters on the under side of the leaf. Dr. Lintner 

 has found as many as 500 in a single cluster, though in our own collecting from 200 

 to 300 were commonly met with, plate 16, figure I. The eggs vary in color from 

 clear white to dull coral red, the deeper color being the sign of the approaching 

 disclosure of the caterpillar. They hatch in about ten days, and the yellowish 

 caterpillars with their prominent black spines behind the head feed side by side in 

 masses. Their presence at this time can easily be detected by the partly stripped 

 branches and also by the fine brownish excrement on the leaves below. July 19, 

 1901, this pest was so abundant at Karner that it was not at all difficult to find one 

 or more of the leaves nearly covered with young caterpillars. The portion of the 

 leaf upon which the eggs are laid is usually untouched, though everything else and 

 the adjacent foliage may have been eaten, plate 16, figure 2. The smaller caterpillars 

 are about ){ of an inch long at this time, and larger, darker ones may attain a length 



