OF WASHINGTON. 389 



ance, as though encrusted with that material. The gall consists 

 of the terminal bud of the shoot, which, from being stung, has 

 hardened into a terminal bud-like gall. The whitish crust on 

 these galls is, more accurately speaking, a brittle resinous efflo 

 rescence from the plant itself. 



One gall, which was opened, was found to contain three 

 orange-colored larvae. It was an extremely dry and dead-looking 

 one. This species of gall does not seem to be very common here, 

 those that were found having been detected by careful search. 

 It was noticed that some of them had been partly eaten into, or 

 perhaps pecked into, by birds ; at least something had evidently 

 been attempting to secure the larvae. 



It was found the next day that a larva had left its gall and was 

 beginning to bury itself in the earth. Most of the remaining 

 galls were opened, but only two more larvae were found within 

 them, indicating that most of the larvae had already left the galls 

 for the earth. 



Cecidomyia chrysopsidis Lcew(?) Cecidomyiidous galls 

 were found September 20, 1890, at Takoma, D. C., on Chrysop- 

 sis mariana, the terminal leaf-buds of the plant being deformed 

 into a gall. These galls occurred in some numbers on hillsides 

 near Takoma. Upon opening the gall, the little orange-colored 

 larvae were to be seen imbedded amongst the bases of the leaves 

 in the deformed bud. 



From one gall collected there issued, about September 24th, a 

 female gnat. It does not quite agree with Loew's description, 

 as it is not at all reddish, but almost entirely coal black. Loew's 

 description of the gall does not seem to apply well either. Pos 

 sibly there are two species of galls on this plant. 



Diplosis resinicola O. S. Three or four exudations of resin 

 on small branches of Pinus inops were found at Vienna, Va., 

 November 23, 1890. One of these, on being slightly cut into, dis 

 closed a bright orange-colored larva, doubtless of this species. 



On opening two of the others, the following day, no larvae were 

 found in the resinous exudation, but in the pith of each twig was 

 found a larva of Retinia comstockiana. The question here arises 

 whether the Diplosis originally causes its own exudation of 

 resin, or whether it dispenses with such labor and inhabits the 

 exudations caused by the larva of Retinia. Osten Sacken says 

 nothing as to what causes this exudation, in his description of 

 this species. No Diplosis larvae were found in the two twigs just 

 referred to, but on February i, 1891, a dead larva of the Retinia 

 was found in its tunnel in the resinous exudation of the twig first 

 mentioned, and in the resin of which a Diplosis larva had been 

 found. It seems certain, therefore, that the midges do at least 

 sometimes, if not as a rule live in the resin which exudes from 

 twigs bored by Retinia. I doubt if the midges ever originally 



