84 



THE I{EPOKT OF THE 



No. 36 



together, as is usually the case, the larval galleries cross and re-cross, completely 

 riddling the bark eventually. The larvse pupate in the ends of the galleries and 

 emerge by cutting each a round hole through the overlying bark. Often, as with 

 many bark beetles, the young adults feed for a short time on the bark before cut- 

 ting through to escape. 



We have two broods of this species. The tunnels of the over-wintered beetles 

 were started the last of May this year in the larch. By July 10th in these tunnels 

 could be found well-grown larvae, pupae and young adults; and light coloured, and' 

 therefore recently transformed adults, were busy starting tunnels in felled larches 

 lying in the clearing. The adults continued to emerge for several weeks, and on 

 August 6th egg-tunnels were being cut and eggs laid in the fallen larch before 

 referred to in connection with D. simplex. So far as my observations go, the tunnel 

 is started by a female, and a male, and other females, join her later. The egg- 

 tunnels are usually kept clean in this species, although more or less boring-dust 

 is at times found in them. They seem to start their tunnels, at times, from the 

 sides of a simplex tunnel, where they are sometimes found exploring during the 

 entrance season. This second brood will apparently mature completely this fall, 

 and hibernate as adults. 



Fig. 6. 

 Work of Ips balsameus in Abies, showing nuptial chamber, egg- 

 tunnels, and egg-niche. The eggs were removed before 

 hatching. 



Ips halsameiis was found on the 10th of July, starting tunnels in a diseased 

 larch in the same bush. I could not be sure that this species had been the primary 

 cause of the injury, apparently not, but certainly halsameus was helping things 

 along merrily. This species breeds chiefly in the fir, sometimes also in the pine; 

 and it frequently attacks and destroys trees, w^hich, while certainly unhealthy at 

 the beginning of the halsameus attack, might otherwise survive. It is to be consid- 

 ered an injurious species in fir and larch. There are two broods each season with 

 us ; the first eggs were laid in pine this season in the middle of May, and the second 

 was, in larch, as just stated, early in July. 



Ips ccelatus — a larger but closely allied species — was numerous in the larch 

 stumps. Its entrance hole is deep, and the nuptial chamber is often entirely in the 



