208 THE CANADIAN ENTOMOLOGIST 
being about one and one-half times the length of the halteres; 
in aspidoptera (fig. 9) the wings are short and broad, and extend 
to about two-thirds the length of the halteres. 
Limnophila (Prionolabis) cressoni,sp. n. 
Dark brown with the thoracic stripes indistinct; wings with 
narrow, grayish brown seams to the cross- veins and deflections 
of veins. 
Male. — Length 8 mm.; wing 10.6 mm. 
Female. — Length 10 mm.; wing 10.8 mm. 
Rostrum short, dark brown; palpi dark brown. Antennae 
short, dark brown; the flagellar segments very short, almost 
rounded, w'ith an abundant white pubescence. Head gray. 
Thoracic dorsum dark brown with a sparse, yellow'ish gray 
bloom, the prsescutal stripes poorly defined. Pleura clearer gray, 
the dorsal-pleural membranes brownish. Halteres dull yellowy 
the knobs a little darker. Legs with the coxae and trochanters 
dull brownish yellow, darkened toward their apices, this dark tip 
broadest on the fore and middle femora, narrowest on the hind 
femora; tibia? brown, the tips narrowly dark brown; tarsi brown. 
Wings with a pale, brown suffusion; stigma dark brown; broad, 
grayish brown seams along the cord, the outer end of cell 1st M2 
and at the origin of the sector. Venation (fig. 7) Ri+z about as 
long as the basal deflection of Cin. 
Abdomen brown, the terminal segments darker. Hypopygium 
of the male with the ninth tergite having a broad, V-shaped median 
notch that is bordered with pale reddish brown; ventral pleural 
appendage with a few^ scattered teeth that are not prominent. 
Female cjuite similar to the male, the ovipositor with elon- 
gate, acute, nearly straight tergal valves; sternal valves elongate, 
only a little shorter than the tergal pair. 
Ilolotype, cf, Lagunitas Canyon, Marin Co., California, March 
29, 1908, (E. T. Cresson, Jr.). 
Allotopotype, 9 . 
The types are in the collection of the American Entomological 
Society, Philadelphia. 
This fly differs from the only described regional member of 
