130 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL, 62. 
Krdéber redescribes Thereva nigra Say in his 1914 paper. He holds 
that 7. melanoneura Loew is identical with JT. nigra and describes 
that species for nigra. There were five males and one female in the 
material, from Colorado and Flagstaff, Arizona. The writer has stated 
above that Say’s description of nigrais unrecognizable. It is certainly 
not melanoneura, which is typically a southwestern species and at the 
time that Say was describing diptera this region was Indian country 
and practically unexplored. 
Two of the species described by Kréber in 1914 are redescribed by 
the writer in the foregoing pages; one of these species, J. bella, was 
kindly determined by C. W. Johnson, the other, 7. niveipennis, was 
originally described as a new species. Translations of the descriptions 
of the four other species of Thereva are given below. 
THEREVA NIVEA Krober. 
1914. Thereva nivea KroseER, Beiheit z. Jahrb. Hamb. Wiss. Anstalten, vol. 
31, p. 64. 
Male—Length 9 mm. Very near 7’. semitaria Coquillett. Dense 
snow white pilose, without silvery reflections. The mesonotum and 
antennae are as in J. semitaria. The halteres are almost white. The 
legs are wholly pale yellowish brown, the femora thick white pilose. 
The anal segment is reddish yellow. The wings are tinged pale yel- 
lowish brown, the stigma not apparent. 
Type locality.—Mesilla Valley, New Mexico, April 19. 
Type.—In the United States National Museum, Cat. No. 26028. 
THEREVA METALLICA Krober. 
1914. Thereva metallica KrOser, Beiheft z. Jahrb. Hamb. Wiss. Anstalten, vol. 
31, p. 68. 
Male—Length 8mm. A species with long wooly white pile. The 
head is strongly metallic, white, shining, only the frontal triangle it- 
self shining black. The pile of the face is unusually long, blackish 
brown, the face with very long snow white pile. The first antennal 
joint is very long bristled, above with black, below with white 
bristles; second and third antennal joints more reddish, gray tomen- 
tose. The occiput is gray, on the eye margin silvery white. 
The mesonotum is black in ground color, dull, with two whitish 
gray, narrow longitudinal vittae. The scutellum is black, gray dusted. 
The pile of the mesonotum is unusually long, sparse, erect, snow white. 
The pleura are so thickly white pilose that the ground color is not 
visible. The abdomen, viewed from in front, is pure metallic silvery 
white, with an intense glitter, as with no other species; the pile is 
long, snow white, sparse. The anal lamellae are reddish yellow. The 
borders of the tergites are not visible. The venter is black, sparsely 
gray dusted, the second segment with a whitish border; the pile is 
long, sparse, white. The halteres are black. 
