arr. 4. REVISION OF THE FAMILY THEREVIDAE—COLE. ae 
Washington: Wapato, May 11 (Cole), [Cole]; Ritzville, June 12 to 
September 9; Sprague, June 20 and Medical Lake, July 14 (all R. C. 
Shannon), [Shannon]. 
Oregon: Forest Grove, July 12 (Cole); Hood River, June 20 (Cole), 
[both Cole]. 
California: Stanford University, May [Stanford U.]; Bradley, May 
22 (EK. P. Van Duzee); Berkeley, September 13; Sisson, July 24 (KH. 
P. Van Duzee); Santa Rosa Island, May 20 (EK. P. Van Duzee), [all 
Cal. Acad. Sci.]; Stanford University, May 20 (Cole); Perkins (W. B. 
Parker); sand dunes near Golden Gate Park, San Francisco, May 25 
(Cole), [all Cole]. 
PSILOCEPHALA LAEVIGATA Loew. 
Plate 6, fig. 55. 
1876. Pstlocephala laevigata Leow, Zeitschr. f.d. Ges. Naturwiss, new ser., vol. 14, 
p. 319. 
Type locality—San Francisco, California. 
The type is in the Museum of Comparative Zoology at Cambridge, 
Massachusetts. 
This species is doubtfully separated from aldrichi; there are appar- 
ently constant though slight differences in the females, but the males 
are hard to distinguish. When larger collections are made of both 
sexes in certain localities the species can be straightened out. The 
females are distinguished from aldricia by the darker wings and 
wing markings and by having the upper half of the frons gray polli- 
nose. (Hig. 55.) There are no doubt slight differences in the male 
genitalia, but these are microscopic and largely internal, or obscured 
by the outer plates. 
Distribution.—Two males and five females were examined, all from 
California. 
There are four females in the Pomona College collection, collected 
at Claremont, California, by C. F. Baker; one female taken at Red- 
lands, California, by the writer. The two males were taken, presum- 
ably, at about the same time as the four females, one specimen in the 
mountains near Claremont, California; no dates are given. More 
collecting around Claremont is necessary before describing the male 
of this species. 
PSILOCEPHALA LATERALIS Adams. 
Plate 6, fig. 62. 
1904. Pstlocephala lateralis ApaMs, Kans. U. Sci. Bull., vol. 2, p. 444. 
Female.—Length 7.5 to 10.5 mm. Closely related to laevigata, the 
head much the same. Vertex gray pollinose; frons smooth, shining 
black, gently convex, the lower corners silvery white (fig. 62), face 
silvery pollinose. Antennae black, first two joints thinly gray polli- 
nose, with a few black bristles; first joint about as long as the third 
