52 



amining the young wood before the tree is leafed out, and picking off and destroying 

 the bunches of eggs; also the picking off and destroying of any cocoons found on the 

 trees— there is often found a leaf folded containing six or seven cocoons. However, :\Ir. 

 DeLong is confident he can exterminate them next season, by placing the greased bands 

 on the trees and shaking off the young caterpillars. 



Fortunately, nature in this case also comes to the rescue, and in 1882 a 

 small fly, belonging to the Ichneumonid^ , became numerous, and the year 

 after it was hardly possible to find a caterpillar. A year ago, 1887, I vis- 

 ited the place, and but very few larva could be found. Specimens, how- 

 ever, have been sent from portions of Sonoma. 



THE FALL WEB-WORM. (Figure No. 41.) 



Hyphantria Cunea (Drury). Order ^ Lepidoptera ; Family, Bomhycidx. 



For the last two years, to my knowledge, the Ameirican black walnut 

 trees {Jugkms nigra), and also some few California walnuts {Juglans cali- 

 fornica) growing on the streets in the town of Santa Cruz, have been infested 

 with a hairy, brownish caterpillar spinning large tents. This year they 

 have especially been numerous. After trying for some time, I finally suc- 

 ceeded in raising a moth, which has been identified by Mr. D. W. Coquilett as 

 the true fall webworm, which is also well described in Professor Riley's report 





/ 





for 1886. The insect has during the last years been very abundant in 

 many portions of the East, and it seems there to have attacked a great 

 variety of trees. I have not seen it feed in nature on any but walnut trees, 

 in fact not on the so called English walnut {Juglans regra), although the 

 tree is abundant in Santa Cruz. However, that it will feed on this species 

 I am satisfied, as leaves of this tree fed in confinement were greedily eaten. 



My poor success in raising so few moths is due to the happy fact that 

 the insect has very numerous parasites, and were it not that these again 

 are being destroyed by still smaller parasites, the fall webworm would soon 

 be a thing of the past. 



Of the parasites found among the debris of the webworm, one has been 

 identified as the Limneria pallipes Prov., a hymnopterous parasite mentioned 

 by Professor Riley as one of the principal destroyers of the fall webworm. 



The followdng description is taken from Professor Riley's report of 1886: 



