3IO , NEW YORK STATE MUSEUM 



The form described, M. perplexa, appears to be closely re- 

 lated toM. diervillae Felt, and it is possible that it is the 

 female of this species. 



Key to species 

 a Antennal segments 8 



b 4th palpal segment more than twice the length of the 3d; harpes 



broadly rounded apically johnsoni n. sp., C. 802 



bb 4th palpal segment nearly twice the length of the 3d ; harpes subacute 



apically cockerelli n. sp., C. 932 



aa Antennal segments 9 



b Subcosta uniting with the margin before the basal half ; wings small, 



narrow (M icromyia) corni Felt, C. 459 



bb Subcosta uniting with the margin at the basal half; wings rather 



large, broad (M i c r o my ia) diervillae Felt, C. 490 



aaa Antennal segments 10 



b Length 1.5 mm; body dark brown perplexa n. sp. 



LESTREMIA Macq. 



This gemis is easily recognized by the characteristic fork of the 

 fourth vein, by costa not attaining the apex of the wing and by 

 the antennae being well developed, those of the male having 16 

 and those of the female 11 segments. The segments of the female 

 antennae are short, subcylindric or siabconical and in some species 

 at least, ornamented distally with thick rows of short, stout, chiti- 

 nous, sensory processes. The male antennae are composed of 16 

 segments, which latter are provided with a distinct stem nearly as 

 long or longer than the basal enlargement, which in turn is orna- 

 mented by one or more crenulate whorls from the base of which 

 arise long, curved setae. The genitalia are very characteristic. 



Nothing is known concerning the life history and habits of mem- 

 bers of this genus, aside from the fact that they are most abundant 

 in the vicinity of forests. Kieffer states that the European L . 

 leucophaea Meig. occurs in decaying beech wood and it is very 

 probable that our American forms breed largely in rotting ligneous 

 tissues. 



Key to species 



a Antennal segments 11; females 

 b Abdomen reddish brown 

 c Scutellum dark brown; basal segment of ovipositor with a length 

 fully twice its width ; terminal segment small, narrowly oval and 



distinctly shorter than the basal segment 



elongata n. sp., C. 933 

 cc Scutellum yellowish brown; basal segment of ovipositor broadly 

 triangular, its length not more than ^ greater than its width; ter- 

 minal segment nearly as long as the basal one, narrowly oval 



b a r b e r i n. sp., C. 934 



