78 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62. 
brown median mesonotal vitta viewed from behind. The pleura ure 
whitish gray. The halteres are blackish brown. The femora are 
black, with dense white pile and tomentum; the tibiae and metatarsi 
are pale yellowish brown. The abdomen is blue gray on the sides, 
almost without shine. The anal segment is pale reddish yellow. The 
wings are intense milk white, the veins whitish, only the first and 
second veins yellowish brown. 
Type locality — Florida. 
Type.—tIn the United States National Museum, Cat. No. 26024. 
PSILOCEPHALA RUGIFRONS Eréber. 
1914. Psilocephala rugifrons KROBER, Beiheft z. Jahrb. Hamb. Wiss. Anstalten, 
vol. 31, p. 54. 
Female.—Very near munda and haemorrhoidalis. The frontal cal- 
lus begins directly over the antennae and is at first smooth rounded, 
then flat and cross wrinkled. The face is black, with dusty pollen, 
not white. The antennae are black, slender, gray tomentose, with 
sparse white pile. The mesonotum is black, dull, seen from the front 
with warm brown reflections and two pale whitish lines. There is a 
shining black stripe from the wing base to the shoulder. ‘The pleura 
are shining black, in part silvery tomentose. The halteres are black- 
ish brown. 
The femora are shining black, the fore femora thick, silvery white 
pilose; the tibiae are yellowish brown, with black tips. The scutel- 
lum is shining black, the outer tip whitish yellow. The abdomen is 
black, shining, almost bare, the second segment broad white on pos- 
terior margin, the fifth segment silvery. The anal segment is red- 
ish yellow haired and bristled. The wings are hyaline, the stigma 
large and blackish brown. 
Type locality—Sierra Madre, Chihuahua, Mexico, 7,300 feet, 
March 6. 
Type.—In the United States National Museum, Cat. No. 26025. 
Genus DIALINEURA Rondani. 
1856. Dialineura RonvDANI, Dipt. Ital. Prodr., vol. 1, p. 155. 
1865. Pachyrrhiza Puitrer1, Verh. Zool.-bot. Ges. Wien, vol. 15, p. 703. 
In this genus are placed the species having a bare face, open cell 
M-3, and an unusually dilated first antennal joint, which is pollinose, 
hairy, and with strong bristles. The species resemble Thereva closely 
and also a few species of Psilocephala. The frons of the female is 
without the shining callosities found in most species of Thereva, and 
the surface is uneven as in Metaphragma, not evenly convex. The 
abdomen is more conical in form than in most species of Psilocephala. 
The males are holoptic and have the genitalia pollinose on the ex- 
