ART. 4, REVISION OF THE FAMILY THEREVIDAE—COLE. 93 
THEREVA SEMITARIA Coquillett. 
Plate 10, fig. 128, and plate 11, fig. 138. 
1893. Thereva semitaria CoQuiLLETt, Can. Ent., vol. 25, p. 198. 
The species more nearly resembles Psilocephala acuta and P. mar- 
cida than any of the species of Thereva, the eyes being shaped as in 
acuta. In the female the frons and face has reclinate, tomentum- 
like pile; the antennal style is black. The vittae of the thorax are 
dark gray, indistinct. The only specimen examined by the writer 
was a female collected at Bradley, California, May 23 (KE. P. Van 
Duzee), in the California Academy of Sciences. This specimen has 
the front femora partially brownish. The veins toward the base of 
the wing are yellowish, blackish beyond, the stigma black. 
Type locality.—Southern California. 
Type.—Male, No. 10421, U.S.N.M. 
THEREVA OTIOSA Coquillett. 
Plate 10, fig. 124; plate 11, fig. 141; and plate 12, fig. 167. 
1893. Thereva oitosa CoQuILLeTT, Can. Ent., vol. 25, p. 199. 
This species is closely allied to vialis and candidata. The wings 
are grayish hyaline, with narrowly bordered veins. (Fig. 167.) 
The frontal spots of the female are quite large. (Fig. 124.) 
Type locality.—Los Angeles County, California. 
Types.—Male, No. 10423, U.S.N.M. 
The outer covering of the male genitalia is gray pollinose, the 
general shape as in vialis Osten Sacken. In the females examined 
the thorax was gray pollinose, marked with brown; there is a broad 
median brown stripe hardly reaching the scutellum and with a faint 
gray longitudinal dividing line, on either side a broad brown stripe 
or mark, broadest above the wing base and not reaching to the 
humeri or scutellum. The first seven abdominal segments are gray 
pollinose, the very narrow base of the second, third, and fourth brown 
on the sides; the pile is short, sparse, and whitish. 
Distribution.--The two males and two females examined were from 
the following localities: California—Claremont (Baker), [Pomona Col- 
lege]; Shasta County (Edwards), [Amer. Mus.]; Crafton, San Ber- 
nardino County (Osten Sacken), [M. C. Z.]. 
THEREVA NOVELLA Coguillett. 
Plate 11, fig. 139. 
1893. Thereva novella CoquitieTT, Can. Ent., vol. 25, p. 200. 
The original description by Coquillett is as follows: 
Male.—Same as otiosa, with these exceptions: Style of antennae two-fifths as long 
as the third joint; pile and bristles of vertex and bristles of occiput yellowish white; 
