70 
Psyche 
[June 
by a comparison of specimens. 1 Both species have practi- 
cally the same peculiar structure of the legs in the male. Brad- 
ley (1922, Univ. of California Publ. Ent., I, No. 9, p. 424) 
writes of the male of P. occidentalis : “the middle tibia seen 
from in front with its inferior edge at the basal third strongly 
dilated and angulate.” As a matter of fact, in that species 
the middle tibia is almost exactly as I describe and figure 
it for P. wheeleri. The two species are, nevertheless, readily 
separated in the males by the shape of the head (eyes not 
bulging in P. occidentalis , separated on the vertex by at 
least five times the diameter of a posterior ocellus, which is 
distinctly removed from the inner orbit), of the four tu- 
bercles of the seventh tergite (the preapical tubercles much 
shorter in P. occidentalis and not sharply carinate at the 
base), and of the process of the third sternite (in P. oc- 
cidentalis the summit is very narrow, with a longitudinal 
groove which is abruptly widened anteriorly). The slight 
differences in the genitalia to be noted between my figures 
of P. wheeleri and those given by Bradley for P. occidentalis 
(1922, Op. cit., PI. X, figs. 62-64) are probably accidental 
and due to the method of preparation. On the other hand, 
the females of the two species are structurally so much 
alike, that after a very careful comparison I can only point 
out the following differences: in P. occidentalis the vertex 
is wider, the inner orbits being there about as far apart as 
at the clypeus and the posterior ocelli being also distinctly 
more removed from the inner orbits than from each other ; 
the clypeus is decidedly longer, being but little wider than 
long. Of course the coloration of the two species is strik- 
ingly different in both sexes. 
Incidentally it may be noted that the character used by 
Bradley in his working key (1922, Op. cit., p. 381) to sepa- 
rate Masaris from Pseudomasaris, viz., postscutellum cov- 
ered or not covered by the scutellum, is not very reliable. In 
P. wheeleri the postscutellum may distinctly be seen in a 
dorsal view, protruding beyond the apex of the scutellum, 
although this is more marked in the male than in the female. 
1 I have been able to examine a pair of P. occidentalis, kindly loaned 
to me by the United States National Museum, through Miss Grace 
Sandhouse. 
