OS PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
slightly backward. Sutural ridge bare. Hairs covering anterior 
spiracle dark brown basally, their tips somewhat lighter; those of 
anterior margin of posterior spiracle dark brown; spiracular cover 
yellowish, brownish toward base. 
^YINGS. — Bend of fourth vein normally a right angle; anterior 
cross-vein usually behind, sometimes slightly more basal than end of 
first longitudinal; third vein bristly; costal spine vestigial; section 
III of costa about equal to section V; alulae fringed with short hair; 
calypters whitish, outwardly fringed with white hair. 
Legs. — -Dark; posterior trochanter with 'brush'; femur subcylin- 
drical, sometimes slightly arched, clothed beneath with long hair; 
upper row of bristles on anterior face complete, two, sometimes three 
intermediate rows present on distal half, their bristles very long and 
stout, only a few weak bristles of lower row retained distally ; posterior 
face of femur, also of tibia, with a dense beard of very long, coarse 
blackish hairs; anterior face of tibia with a similar beard of shorter, 
less dense hairs on the distal three fourths; tibia straight or slightly 
curved; tarsus shorter than tibia. Middle coxa with a single row of 
bristles; femur with long fine hair on its posterior ventral surface, 
especially proximally; submesotibial bristle present. Anterior coxa 
with two rows of bristles. 
Chaetotaxy. — Anterior dorsocentrals somewhat shorter than post- 
suturals; acrostichals present, long and slender; three pairs posterior 
dorsocentrals, all long; prescutellar acrostichals fine and hair-like, 
sometimes wanting; scutellar apicals present, slender; three sterno- 
pleurals. 
Abdomen. — Elliptical in outline. 
Chaetotaxy. — Second segment without marginal bristles; third 
with two strong ones at center and weak slender ones between these 
and laterals; fourth with a complete row of bristles ending ventrally 
in a group of long hairs. 
Genital segments. — When in normal position so held that ventral 
parts of fourth notum are spread apart and downward : first segment, 
either dull orange throughout or anterior part grayish pollinose or 
brownish even nearly back to marginal bristles, but ' humps ' generally 
not darkened; sparingly yellow pollinose centrally; vestiture short, 
in profile with a shallow depression anterior to bristles; second, dull 
orange, in shape roughly resembling a spherical segment with its 
plane surfaces nearly equal ; anal area prolonged upward nearly to top 
