February, 'IG] 



HOUSER: DASYNEURA ULMEA 



83 



the infestation was but slight. A curious, and thus far unexplained, 

 feature of the problem is that the pest exhibits a preference for indi- 

 vidual trees, wherein a given specimen may be rather severely attacked, 

 while nearby neighbors of the same species are but slightly, if at all 

 infested. Thus far, white elm, Ulmus americana, only has been ob- 

 served to be injured. 



As previously stated, the adult has been described by Dr. Felt. 

 The egg and pupal stages have not been observed by the writer, but 

 larvaB may be found 

 in abundance in the 

 galls of infested 

 trees from midsum- 

 mer until spring. 

 Usually more than 

 one larva occurs 

 within a -single gall, 

 in some instances as 

 many as eight hav- 

 ing been found. In 

 two cases larvae of 

 different sizes, some 

 very small and some 

 apparently two- 

 thirds grown, were 

 found within the 

 same gall. Where 

 more larvse than 

 one occur, they are 

 not separated from 

 one another by the 

 gall tissue but lie in 

 a mass in the center 

 of the gall. There 

 is probably but one 

 brood per season. The individual larvse are pink or flesh in color, 

 3.5 mm. long and 1 mm. broad. They are typically Cecidomyid and 

 possess the "breast bone" like organ and ability to spring into the air 

 characteristic of many of the larvse of this family. 



Parasitism is quite common, the adult parasites emerging through 

 circular holes cut through the walls of the upper half of the gall. Only 

 one species has been reared, determined by Mr. S. A. Rohwer, of the 

 Bureau of Entomology, as Callimome sp. The parasites seem to be in 

 no wise as sensitive to the drying up of the galls as do the midges, 



Fig. 7. 

 larged. 



Dasyneura ulmea; typical galls slightly en- 



