HICKORY BARK BORER. 269 



but penetrate the small branches and even the twigs. The entrance 

 to the twig is usually made at the axil of a bud or leaf, and the channel 

 often causes the leaf to wither and drop, or the twig to die or brtak 

 off." 



Packard* considers this the most destructive bark borer 

 attacking the hickory. 



Both sexes are dark brown or nearly black, the thorax darker 

 than the wing-covers. There are numerous hairs upon the head, 

 forming a brush which may perhaps be useful in cleaning out 

 the galleries. This brush is more strongly developed in the 

 male than in the female and is well shown in the left hand figure 

 of the beetle on Plate VIII, a. Thorax and wing-covers are 

 about equal in length, and the abdomen, which is shorter than 

 the wing-covers, is truncated in a peculiar manner. The abdo- 

 men and thorax are more or less hairy on the ventral surface in 

 both sexes, and some specimens have dorsal hairs on the front 

 portion of the thorax and at the posterior extremity of the wing- 

 covers. 



On the end of the truncated abdomen, in the male there are 

 four spines, which fact evidently suggested the specific name. 

 The female, however, is not provided with these spines and the 

 ventral portion of the abdomen is smooth. The beetles vary 

 considerably in size in both sexes. Those examined by the 

 writer were somewhat larger than the specimens studied by 

 Riley and described as 5. carya in the Fifth Report of the State 

 Entomologist of Missouri, page 107. Riley gives the length 

 as from .15 to .20 inch, while the specimens which the writer 

 observed varied from .20 to .25 inch. 



The brood gallery, which is formed between the bark and 

 the wood, consists of a short vertical tunnel from which branch 

 at right angles from twelve to seventeen smaller galleries on 

 either side. These side tunnels are excavated by the young, 

 each making a separate burrow, and though often very near 

 each other never seem to cross, and are nearly parallel on each 

 side of the central chamber. As the larvae increase in size 

 the tunnels diverge somewhat so as not to run into each other. 



Miss Hillhouse states that no dead and dying trees were 

 marked and cut, and that later several more were removed from 

 the grove. From what we know of the habits of the Scolytidae, 



* Fifth Report, U. S. Entomological Commission, p. 285, 1890. 



