arr. 4, REVISION OF THE FAMILY THEREVIDAE—COLE. 13 
they have been confused; the latter species is described in the present 
paper and has spread farther west and north than haemorrhoidalis, 
all the Canadian specimens examined belonging to this species. 
The genus Henicomyia is undoubtedly Mexican in its origin; prob- 
ably the same is true of the new genera Caenotus and Pherocera and 
the genera Huphycus, Ozodiceromyia, and Furcifera. The genus 
Chromoleyida is known from two species, one occurring in Nicaragua 
and the other in central California; the two species are very nearly 
alike and the Central American form was described by Coquillett as 
aspecies of Psilocephala. Metaphragma is represented by one species 
which occurs all along the Pacific coast and the one known species of 
Nebritus is reported only from California. 
GEOLOGICAL DISTRIBUTION. 
Several species of Therevidae have been described from fossil 
remains in Kurope, three species having been described from Baltic 
amber by Loew. The specimens described have been assigned to 
the lower Oligocene, upper Oligocene, and upper Miocene. Scudder ® 
mentioned a series of specimens taken at Florissant, Colorado, but 
did not describe any of the species. They were taken together with a 
number of Asilidae and many of the specimens were in good condition. 
In 1909 Cockerell described two species from the Miocene shales 
of Florissant, Psilocephala scuddert and P. hypogaea, which are re- 
ferred to in the bibliography. Both species seem to be quite closely 
allied to modern species of the genus Psilocephala. In the Proceedings 
of the United States National Museum (vol. 57, p. 251, 1920) Cock- 
erell describes a new genus and species, Hothereva simplex, from Eocene 
rocks. This fly is described as similar to Thereva, but with very 
long antennae, the second joint longer than the other two together, 
and the third longitudinal vein of the wing simple. The discal cell 
is described as small and narrow, the anterior cross vein equally 
distant from its base and apex, the anal cell probably open, perhaps 
widely so. The species is 6 mm. in length, of which 3.4 mm. is abdo- 
men; the wings about 5.5 mm. and reddish hyaline. The body as 
preserved is described as pale reddish. 
TABLE OF GENERA.? 
1, Thorax and abdomen largely clothed with scales, many of which ars iridescent; 
face below the antennae with two shining callosities; antennae long, slender, 
short bristled, and with a small subapical style.... Chromolepida, new genus. 
Body with a tomentumlike pile, but never with scales; face without shining 
tubercles; third antennal joint with a style (except in Henicomyia)....... 2. 
2. First antennal joint longer than the head and well developed............. Bi 
First antennal joint at most as long as the head, usually much shorter. .... 4. 
§ Bull. U. S. Geol. Surv. Terr., vol. 6, p. 291, 1881. 
7The genus 4 psilocephala described in Kréber’s 1914 paper is near Pherocera, but has very slender 
wings and no stigma. 
