THE LEAD-CABLE BORER IX CALIFORNIA. 17 



liave started to color. The wing pads now commence to swell and 

 on about the fifteenth day from pupation the struggles of the insect 

 split the pupal skin, the wings and elytra spread over the dorsum of 

 the abdomen, and the transformation to the adult has taken place. 



The Immatuke Adult. 



At first the elytra of the young beetle are dull white and rather 

 soft and the small punctures very distinct. The elytra slowly color 

 to light brown, dark brown, and finally black. The abdominal seg- 

 ments also blacken, and in about one month or six weeks the beetle 

 appears full grown. It slowly bites its way to the surface of the 

 infested section and some warm dsij emerges as a fully matured 

 beetle. (Fig. 4.) 



The Mature Adult." 



General description. — Form cylindrical, head deflexed; size small 

 (average length. 5.85 millimeters; average width, 2.10 millimeters) ; 

 the prothorax and abdominal sternites about equal in length. Color 

 dark brown to black, mostly black; antennae, mouthparts (except 

 mandibles), femora, and tarsi light amber; tibiae, posterior lateral 

 area of prothorax, and tumid area on the anterior lateral portion of 

 elytra dark amber. 



Emerging. — As soon as the adult becomes mature it slowly bites 

 its way to the surface and, selecting a warm day, emerges from the 

 section of wood. The emergence hole can be distinguished by its 

 sharp, square edge and by the fact that usually it is in the open and 

 not hidden in a crevice or similar place. If the weather conditions 

 are not suitable, the beetle will often turn around and go back into 

 the emergence hole for a time before it finally leaves the section. 



Flying. — -Both sexes are strong fliers and are on the wing a good 

 deal if the weather is warm. 



Feeding. — After emergence the males appear to get under a bark 

 scale or similar place and feed while they wait for the females to 

 start their entrance galleries into the new wood. The females do 

 not appear to feed until they have the entrance gallery well started 

 and are into the wood. None were observed to feed on the bark. 

 The male often comes to the gallery and feeds on the borings thrown 

 out by the female. 



Boring. — Apparently most of the boring is done by the female. 

 The male may make a short food gallery or impression, but the egg- 

 gallery is made by the female. Soon after emergence she seeks a 

 suitable place in which to deposit her eggs. Finding such a place at 

 a knot, scar, bark scale, or crevice in or under the bark or in the wood. 



" For a detailed description of the mature beetle, see Appendix, p. 54. 

 2047—22 3 



