140 Psyche [October 



breeding are very similar to those of P. granulatus, the chief dif- 

 ference being in the shorter egg-galleries apparently characteristic 

 of P. nudus. 



Insects derived from the same material and associated with P. 

 nudus include P. granulatus Sw., P. cariniceps Lee, P. puberulus 

 Lee, Pityogenes hopkinsi Sw. and the clerid Phyllobaenus dis- 

 locatus Say. 



Pityophthorus puberulus LeConte. 



Pityophthorus puberulus Lee. is apparently distributed over the 

 eastern portions of the United States and Canada and according to 

 Swaine 1918 (loc. cit.) breeds in pine and balsam fir. The writer 

 has found it in central New York only a few times but whenever 

 found it always seemed to occur in immense numbers. The 

 beetles attack the terminal twigs and smallest limbs of diseased or 

 dying white pine branches. Occasionally it also attacks healthy 

 terminal twigs as well, but seems to prefer most of all the twigs of 

 branches freshly broken from the trees. 



The adults bore through the bark of the smallest twigs at the 

 bases of the pine needles and eat not only the inner bark but also a 

 considerable part of the wood (Plate IX, fig. 4, b, c, d, e, f). They 

 often penetrate into the center of the twig and sometimes continue 

 their feeding burrow in the pith for some distance. These bur- 

 rows in the smallest terminal twigs are primarily feeding burrows, 

 although not entirely so. 



One peculiarity in the feeding of P. puberulus is their apparent 

 fondness for pitch. As a rule scolytids, even species which have 

 demonstrated their ability to live in burrows flooded with pitch, and 

 to dispose of this by the construction of pitch-tubes, avoid pitch- 

 pockets and pitch-sinuses when possible. P. pubendus, however, 

 shows no such avoidance of the numerous pitch sinuses, which ex- 

 tend longitudinally in the inner part of the more or less abnormal 

 bark of diseased or broken limbs. On the contrary, when the bur- 

 rowing beetle taps one of these sinuses, it seems nearly invariably 

 to continue its mine along the course of the cavity. This species 

 seems to have solved the question of manipulating the pitch not by 

 removing it from its burrow and building it up around the entrance 

 in the form of a pitch-tube, but to a great extent at least by eating it. 

 When a pitch-sinus is tapped and the pitch begins to flow into the 



