136 



MISC. PUBLICATION 273, U. S. DEPT. OF AGRICULTUllP] 



lock and is sometimes suspected of killing such trees. It is distributed 

 through the Rocky Mountain and Pacific coast regions, where it also 

 is found breeding in Douglas fir, balsam firs, and sometimes in pines. 

 The adults are elongated, velvety brown beetles about one-half inch 

 in length and are in flight from May to August. The larvae feed in 



the bark, where they 

 construct irregular, 

 Avinding nunes which 

 sometimes complete- 

 ly encircle the tree. 

 During the later 

 stages of larval de- 

 velopment they may 

 enter the w^ o o cl to 

 pupate, or pupate in 

 the bark. 



The ponder osa 



])ine bark borer 



{Acanthocinus spec- 



fahilis Lee.) (fig. 



67), in the larval 



9# '11 ^%r ^liiiWBMM?^^""- ' "I^M^ stage is the large 



w'/'m ^fl^^^^^^^B '1"^^^ white grub so com- 



W^'. «&. ^1^^ j>^^^m^ ^^>^i^f^ monly found in pon- 



derosa pines killed 

 by the western pine 

 beetle, and is some- 

 t i m e s mistakenly 

 supposed to be the 

 insect responsible 

 for the death of the 

 trees. It also occurs 

 in other pines. These 

 insects are more ben- 

 eficial than other- 

 wise, in that they rob 

 the bark beetles of 

 their food. The 

 adults are large, 

 speckled, gray bee- 

 tles with extremely long feelers, and the female has a long, hornlike 

 ovipositor extending from the end of the abdomen. 



The locust borer {Cyllene robiniae Forst.) {22^ 3Ji.^ 1^5) (fig. 68) 

 is well known as an economically important insect pest of locust in 

 the Eastern States and has spread as far west as Colorado and east- 

 ern Washington. The adults are someAvhat slender, one-half to two- 

 thirds of an inch in length, black, heavily marked with yellow, and 

 with reddish legs. The markings on the wing covers or elytra con- 

 sist of zigzagged and broken lines, and on the thorax and body are 

 narrow yellow bands. The adults appear late in summer and lay 

 their eggs in the crevices of the bark. The larvae bore irregular, 

 winding galleries into the sap wood and heartwood of locust and 



Figure 67. — Larva and work of the ponderosa pine bark 

 borer (Acanthocinus spectaMJis). The borings are shown 

 crossing those of the western pine beetle. Insert : A. 

 Male beetle ; B, female beetle. All natural size. 



