62 Psyche [April-June 



From the foregoing it would appear that Trachypetus is a very 

 generahzed Braconid, perhaps best placed in the subfamily Hel- 

 coninse as at present understood unless it be separated as Schulz 

 has done as a monotypical subfamily known only by one species 

 in one sex, a position of very doubtful stability. As I believe that 

 the present unsatisfactory classification of the Braconidse as a 

 whole can be improved only by a careful examination of the quite 

 considerable number of apparently aberrant forms, I have taken 

 this occasion to discuss and figure Trachypetus. 



AN INFESTATION OF THE WIIITE-PINE APHID. 



By H. B. Peirson, 

 Bussey Institution, Harvard University. 



Wliile working at the Harvard Forest, Petersham, Mass., my 

 attention was called to a somewhat isolated clump of white-pine 

 trees, forty to fifty years old, which were dying. The trees averaged 

 about fourteen inches D. B. H. and were approximately twelve in 

 number. On two sides of the clump of mature trees were young 

 white-pine plantations. A careful examination showed that the 

 trees were being killed due to an extremely heavy infestation of 

 black aphids which upon identification proved to be Lachnus 

 sir obi Fitch., the White-pine Aphid. Many of the larger limbs were 

 barren of foliage, whereas on others the foliage was brown, the 

 individual needles each showing many puncture marks where the 

 aphids had been feeding. 



The trees were first examined October 10, 1919, at which time 

 the aphids were laying their eggs on the needles. These are laid 

 end to end generally in lines of five or six, although as many as 

 twenty-seven were found on a single needle, and it was not at all 

 uncommon to find as many as ten or fifteen attached end to end. 

 The eggs were invariably laid on the green needles, and the aphids 

 apparently anticipating the death of the older trees were laying 

 the majority of the eggs on the younger trees in one of the adjacent 

 plantations. Practically all of the needles on the more heavily 

 infested trees had batches of eggs on them. 



Large numbers of the aphids were still feeding. These had 

 congregated on the needles and small twigs. The survival of the 



