83 



THE REPORT OF THE 



No. 36 



distal end of the egg-tunnel ; the pupae in the ends of larval tunnels arising nearer 

 the entrance hole; the light-coloured adults in tunnels arising still nearer the 

 entrance hole; and, lastly, the darker adults in tunnels coming from the proximal 

 end of the egg- tunnel. 



On the same day, August 6th, this species was found in large numbers start- 

 ing tunnels in a felled larch which lay near the stumps just referred to, but shaded 

 by standing trees. A few felled larches lay in the open clearing, but these were 

 not attacked. Egg-tunnels of this second brood were also found in many of the 

 stumps. A standing larch, evidently dying, contained many fresh tunnels of Ips 

 balsamcus but none of D. simplex. 



The tunnels of simplex in the fallen larch were, on Aug. 6, usually well 

 started, with numbers of eggs already laid, but no eggs had hatched. Very evi- 



Fig. 4. D. simplex, Lee. An egg-tunnel showing egg-pocket, e.p., containing eggs; turn- 

 ing niches, t.n., and entrance-hole, e.h. 



Fig. i. D. simplex. Development of larval galleries; larvae half-grown, e.t., egg- 

 tunnels; l.g., larval galleries; larvae were working in the clear spaces. 



dently we had there a second brood, although I did not actually trace the newly 

 transformed beetles from the stumps to the felled tree, and one brood a season has 

 hitherto been recorded for this beetle. 



The egg tunnels are about % inch wide, although the width is very irregular 

 in the different parts of the tunnel. In an egg-tunnel recently started, the half 

 nearest the entrance hole will be packed tightly with chips and excrement, and in 

 the distal — empty — half will be found the beetles, a pair or more. In some I have 

 found one female and as many as three males. As the tunnel is lengthened, the 

 refuse, chips and excrement, is packed towards the entrance, leaving always a short, 

 clear space at the distal end. As the tunnel increases in length, shallow pockets 



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