96 Psyche [August 



same stumps as Hylurgops. Other beetles frequently associated 

 are Dendroctonus valens Hopk., Dryocoetes americanus Hopk., Ij)s 

 pini Say, Ips calligraphus Germ., Cossonus corticola Say, Mono- 

 hammus confusor'KiThy, M. titillatorFahr., Rhagium lineatum OMv ., 

 Pytho americmius Kirby, and occasionally Gaphisurus fasciatus 

 DeG., and Ips longidens Swaine. Associates occurring in the feed- 

 ing burrows of the young adults include Glischrochilus sanguinolen- 

 tus Oliv., and several other unidentified nitulids and staphylinids. 



Explanation of Plate IV. 



Fig. 1 . View of the inner bark of white pine showing the brood- 

 burrows of Ips longidens. In the egg-gallery shown below, the 

 plugs of white frass by which the eggs are retained in their egg- 

 niches are still plainly visible although the eggs have hatched long 

 since. About three-fourths natural size. 



Fig. 2. Engraving made by Ips longidens on the surface of the 

 wood of white pine. The nuptial chamber (a), two transverse, 

 (b) and one longitudinal (c) egg-galleries with their egg-niches, 

 larval burrows (d) and the feeding burrows (e) of the young adults 

 are shown. About two-thirds natural size. 



Fig. 3. Brood-burrow of Hylurgops pinifex in the inner bark 

 of white pine. Note the entrance gallery (a), the nuptial recess 

 (b), the egg-gallery (c) with the egg-groove along the right side, 

 the turning niche (d) and the burrows of the young larvae (e). 

 About one-half natural size. 



Fig. 4. Fragment of the bark of white pine showing the pupal 

 chamber of Hylurgops pinifex. About three-fifths natural size. 



