22 



SOME INSECTS INJURIOUS TO FORESTS. 



])lanie for the trouble. There were many trees which had l)een dead 

 for from 8 to 10 years, and m the l)ark of those dymg within the past 

 4 years traces of the characteristic galleries of D. hrevicomis were 

 found. No large bodies of timber had died, but the dead and djang 

 trees were scattered all through the forest. A few examples of adults 

 were found mining in living l)ark of a dying tree, wdiere they had 

 evidently passed the winter, since none of the broods had sufficiently 



matured to emerge. April 26, eight 

 large trees — five western yellow pine 

 and three sugar pine — which had evi- 

 dently died in 1897, were observed in 

 the Slate Creek Valley. The western 

 yellow pine exhibited abundant work 

 of Dendroctonus hrevicomis, and the 

 sugar pine the work of both this and 

 a larger species of the same genus 

 {D. ■monticolse,) . 



Buckeye, Wash, {near Spokane), 

 May 22. — A small western yellow 

 pine tree, evidently killed by the in- 

 sects, was found. None of the brood 

 had emerged , having died in the bark, 

 possibly from the effects of unfavor- 

 able climatic conditions. In another 

 tree "killed by this species at this place, young living adults were 

 found. 



Cedar Mountain, Idaho {near Moscow) , June Jf.. — The bark of western 

 yellow pine trees defoliated by pine butterfly larva^ was found to be 

 infested by larvae and pupse of D. hrevicomis. Dead parent adults, 

 also, were found in the primary galleries. 



Mariposa County, Cal., June 9, 1904- — Fragments of dead adults 

 were found in primary galleries in ba'rk of a large western yellow pine 

 tree, evidently killed by this species. 



Yoseniite Valley, California, June 13, 1904- — Western yellow ]:)ine 

 trees cut between September 20 and 24, 1903, were found to ])e 

 thickly infested with larva) of this species from eggs evidently de- 

 posited in September or October. 



Fig. 10. — The western pine-destroying bark- 

 beetle {Dendroctonus brevicomis): a, pupa, 

 ventral view; b, same, dorsal view. Ver- 

 tical line in center represents natural 

 length (original). 



OBSERVATIONS BY H. E. BURKE, 1904. 



From Octo])er 20 to 26, 1904, Air. Burke found the work of this 

 species on western yellow pine quite abundant in the region of Smiths 

 Ferry, Idaho. ITnder date of October 26 he records observations 

 regarding this barkbeetle in a western yellow pine tree 3 feet in diam- 

 eter felled some time during that summer; the foliage and bark were 

 living, but red borings on the bark showed where insects had entered. 

 Adults of the Dendroctonus were present in short winding galleries 



