6 BULLETIN 1066, U. S. DEPARTMENT OF AGRICULTURE. 



ADULT. 



The beetle (PL I, A, Z», and C) resembles very closely the common 

 plum curculio, being brownish gray with a variable, whitish, curved 

 line on each side of the thorax and a broad whitish band behind the 

 middle of the elytra. The back is marked with prominent humps and 

 ridges and is covered with short gray and whitish pubescence. The 

 strong curved beak is nearly half as long as the body, and the body, 

 exclusive of the beak, averages about 7 mm. in length. The general 

 appearance of the beetle is rough and angular. 



The young beetles issue from the soil in late summer and early 

 autumn, 64 individuals issuing in West Virginia between August 17 

 and September 6. Of these beetles the maximum daily emergence of 

 13 took place on August 27. A few beetles continued to come from 

 earth in rearing jars up to the middle of October. These young 

 beetles reach the trees before those of the parent generation have all 

 died, and, like them, feed sufficiently in the autumn on the surface of 

 terminal shoots and leaf petioles to suggest their destruction with 

 arsenical sprays in September or early October. The beetles go into 

 hibernation, probably in litter on the ground, with the approach of 

 freezing weather. 



The beetles issue from hibernation in the spring at about the time 

 walnut trees come into bloom and resort at once to their host trees. 

 They may at this time be jarred in abundance from butternut trees, 

 a few having been taken in West Virginia by jarring black walnut 

 and hickory trees growing near butternut trees. With very few ex- 

 ceptions, however, the species jarred from black walnut at this season 

 of the year has been C. retentus and those from hickory C. aratus. 

 This usually holds good even where the three kinds of trees grow in 

 close proximity. 



Feeding begins in a limited way soon after the beetles appear on 

 the trees, the food consisting of stem and leaf tissues of the new 

 growth. The feeding marks in the stems are in the form of irregu- 

 lar pits reaching through the bark and are sometimes extensive 

 enough to cause the leaves and tips to droop and die. Oviposition 

 soon begins, the first eggs being laid in the new growth which forms 

 before the fruit is large enough to be attacked. In the native butter- 

 nut most of the eggs are withheld until the nuts are large enough to 

 receive them, this being when the nuts are about an inch long. In 

 young and tender nuts practically all the eggs are placed in crescent- 

 shaped marks eaten into the husk near the blossom end. (PL I, E ; 

 PL II, A.) By means of an extrusive ovipositor the egg is thrust 

 into a small pocket excavated beneath the tongue of skin on the con- 

 cave side of the crescent. The beetles are often found resting upon 

 the remnants of the blossom that project from the tip of the young 



