90 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.54. 



Thorax. — Mesonotum clothed with rather short, reclinate bristles. 

 Hairs covering anterior spiracle light yellowish except at very- 

 base; those of anterior margin of posterior spiracle mostly dark 

 brownish but faintly lighter at very tips; those of spiracular cover 

 light yellowish throughout. 



Wings. — Bend of fourth vein a right or very slightly acute angle; 

 anterior cross-vem more basal than end of first longitudinal; third 

 vein bristly; costal spine vestigial; section III of costa about one 

 and one haK times section V; alulae fringed with hair; calypters 

 whitish, margins fringed with whitish hair. 



Legs.— Dark. Posterior femur clothed beneath with fine hairs 

 that do not become longer and beard-Uke posteriorly; anterior face 

 with three rows of bristles, those of intermediate row shortest and 

 absent distally; posterior face without ventral row of bristles; tibia 

 straight or slightly curved, only the posterior face with a weak beard 

 of long, coarse hairs on distal two-thirds to three-fourths; tarsus not 

 shorter than the tibia. Middle femur clothed beneath on posterior, 

 proximal half with beard-hke growth of long hairs; anterior ventral 

 row of short bristles complete, posterior row represented by ''comh" 

 only, which extends back to the long hairs: submesotibial bristle 

 present. Ventral surface of anterior coxa with an irregular row of 

 bristles at each side only. 



Chaetotaxy. — Anterior dorsocentrals not weaker than anterior 

 postsuturals and longer than vestiture of prescutum; acrostichals 

 absent; inner presuturals very weak: last two pairs of posterior 

 dorsocentrals much the stronger, anterior to these two or three 

 pairs scarcely longer than vestiture of scutum; prescutellar acros- 

 tichals present; scutellar apicals present; three sternopleurals ; lower 

 sternopleura with a single row of bristles, otherwise clothed with hair. 



Abdomen. — Somewhat conical or slightly oval, clothed above 

 with short, reclinate bristles, beneath with longer, more erect hair 

 that becom.es much longer on fourth notum. Vestiture of fourth 

 ventral plate very short and strongly reclinate or decumbent. 



Chaetotaxy. — Second segment without marginal bristles; third 

 with two, and with two or three laterals on each side; fourth with a 

 complete row ending ventrally in long hairs. 



Genital segments. — Not prominent, usually only second segment 

 and membranous band between it and first showing, ground color 

 usually black or blackish but sometimes brownish. First, some- 

 times faintly grayish pollinose, in profile slightly arched, marginal 

 bristles absent; second, rotund, very slightly flattened, vestiture 

 slightly longer than that of first; anal area small. Forceps black or 

 blackish, base with long, slightly curly hairs a little longer than 

 vestiture of second segment; prongs approximated for about half 

 their length, tips bare. Connecting membrane, on each side just 

 anterior to "humps," with a row of long hairs. 



