INSECT ENEMIES OF WESTERN FORESTS 



199 



jury which may kill the tree. These injuries to the living tree often 

 appear as serious defects when the tree is converted into lumber. 

 The carpenter moths, belonging to the family Cossidae, principally 

 attack broadleaved forest, shade, and fruit trees. The adults are 

 large, mottled-gray moths, with spindle-shaped bodies and narrow, 

 strong wings of medium to large size. They are night fliers and 

 lay their eggs in bark crevices or on old wounds. The caterpillars, 

 which are nearly hairless, have both true legs and abdominal pro- 

 legs but are somewhat grublike in form. Pupation occurs within 

 the larval gallery, and when about ready to change to the adult 

 the pupa works partially out of the burrow, so after emergence 

 the empty pupal skin is found protruding from the tunnel. 



Figure 95. — The carpenter worm (Prionoxystus robiniae) : A, Adult moths, 

 X 0.5, male above; B, eggs, X 3; C, larva, X 0.5; D, pupae, X 0.5; E, 

 borings in trunk of tree. (Drawings by Edmonston.) 



The carpenter worm (Prionoxystus robiniae (Peck) ) (fig. 95) 

 is the most common representative of this group. It probably is 

 the most destructive insect enemy of oaks in California, but also 

 attacks poplars, cottonwood, ash, maple, willow, and other shade 

 and fruit trees. It is distributed generally throughout the United 

 States. The adult females are gray moths with a wing expanse of 



