1915.] NATURAL SCIENCES OF PHILADELPHIA. 477 
Fe?nale. — Length, 15 mm.; wing, 10.5-11.8 mm. Middle leg, 
femora, 4.9 mm.; tibiae, 4.5 mm.; hind leg, femora, 6.3 mm.; tibiae, 
6.6 mm. 
Frontal prolongation of the head rather short, brownish yellow 
with sparse black hairs above; nasus distinct; palpi with the first 
two segments dull yellow, the apical segments darker. Antennae 
long, graceful, if bent backward extending about to the base of the 
fifth abdominal segment; the three basal segments dull yellow, the 
remaining segments dark brown, uniform or nearly so. Front with 
a tubercle, grayish passing into bro^\^l on the vertex and thence 
into bufiF on the occiput; frontal tubercle buff; a narrow black 
median vitta from this latter becoming indistinct about the middle 
of the vertex. 
Pronotum dull yellow to brown. Mesonotal prsescutum dull 
grayish yellow with three distinct dark broAvn stripes, the median 
one broadest, the lateral stripes small and less distinct; scutum 
pale yellow laterally, duller yellow medially, the centre of the lobes 
mostly dark brown; scutellum and postnotum dull yellow, whitish 
pollinose. Pleura pale yellow, whitish pollinose, with brown mark- 
ings before the base of the halteres, on the mesepisternum and 
mesosternum; metanotum brownish. Halteres light yellow, the 
knob dark brown. Legs with the coxae pale whitish pollinose, the 
cephalic faces more or less suffused with brown, especially on the 
hind legs; trochanters and femora yellow, the latter narrowly dark 
brown at the tip; tibiae brownish yellow passing into dark brown 
at the tip; tarsi dark brown. Wings pale yellowish brown, sub- 
hyaline, the costal region more yellowish, the stigma more brownish 
but indistinct; an interrupted vitreous band from before the stigma 
into cell IstM^; a vitreous spot beyond stigma in the base of cell Ri 
(see Plate XVI, fig. 8). 
Abdomen with the first tergite silvery pollinose basally, bright 
yellow on the terminal two-thirds; tergites two to four dull yellow, 
each segment with a black median triangle, the point of which is 
behind; segment two with a dark brown ring about midlength of the 
sclerite; segments three and four with this transverse ring subbasal; 
lateral margins of these segments broadly pale yellow, inside which 
is a broad dark brown band running the length of the abdomen; 
segments five to seven dull yellow with the dorsal triangles and the 
lateral pattern extensive, largely covering the segments; the black 
lateral stripes end at the base of segment seven, so this segment is 
largely yellowish on the sides; segment eight dark brown except 
