142 Psyche [October 



thus aiding in the production of clear timber. The role they play 

 in hastening the reduction of broken twigs and limbs to humus is 

 also mildly beneficial. 



Pityophthorus cariniceps Lee. and Pityogenes hopkinsi Sw. are 

 often associated with Pityophthorus puberulus in storm-broken 

 limbs of white pine, while Pityophthorus granulatus Sw. and P. 

 nudus Sw. frequently occur in the same suppressed pine limbs, and 

 the work of all three combine in aiding in the death of such parts 

 and thus hastening natural pruning. Other insects occurring in 

 the larger portions of suppressed limbs, include Chrysobothris 

 dentipes Germ., C.femorata Fabr., Pogonocherus mixtis Hald., and 

 Leptostylus sexguttatus Say. 



Explanation of Plates. 

 Plate VII. 



Fig. 1. Brood burrows of Pityophthorus cariniceps in small 

 storm-broken limbs of white pine. Note the coarse egg-galleries 

 grooving the sapwood deeply and containing relatively few egg- 

 niches. About four-fifths natural size. 



Plate VIII. 



Fig. 2. Section of upper trunk of a small suppressed white 

 pine showing the characteristic engravings made by Pityophthorus 

 granulatus. Note the long fine egg-galleries with rather sparsely 

 placed egg-niches from which the larval mines originate. The 

 brood burrow originating in the center has 7 egg-galleries while 

 that near the bottom has 9. About five-sixths natural size. 



Fig. 3. Two adjacent pieces of a smaller limb showing brood 

 burrow of P. granulatus having 6 egg-galleries. One of these 

 marked "a" reaches a length of 250 mm. (10 inches). About 

 four-fifths natural size. 



Plate IX. 



Fig. 4. Brood burrows and feeding burrows of Pityophthorus 

 puberulus. "A" brood burrows in small limb 6 mm. in diameter; 

 b, c, d, e, and f burrows in the smallest leaf bearing twigs of white 

 pine. All magnified about 2| diameters. 



