194 
Hippoboscidae (Diptera Pupipara) 
Male (Fig. 10). Differing from tlie male of M. ovinus ovinus (Fig. 8) in 
the following particulars especially. Setae everywhere tending to be larger 
and more numerous, the difference in size being especially conspicuous on 
the dorsum of the thorax; abdomen above without a bare apical space as in 
the male of ovinus ovinus ; scutellum apparently lacking and no scutellar setae 
present, while in the typical form the scutellum, although very small, is 
distinct and bears a cluster of apical setae. 
There appears to be a slight difference in the antennae, the typical form 
(Fig. 9 C) having the apical setae much longer than they are in montanus 
(Fig. 9 E). The wing vestiges, genitalia and claws seem to be the same as in 
the typical form (Fig. 9 A, B, D). 
Notes. While these two forms are certainly closely related we cannot but 
regard them as worthy of distinction. The differences are small, but upon a 
direct comparison of specimens are sufficiently evident. A sufficient amount 
of material of the typical form has been examined without evidence of variation 
to reduce the chance that montanus is simply a variant. 
A comparison with M. ovinus fera Speiser is not possible, for the description 
of this form consists merely of the statement that “sie ist etwas schlanker, 
etwas heller und etwas kleiner” than the typical form. 
Genus Olfersia Wiedemann. 
Olfersia americana (Leach). 
Figs. 11, 12. 
1905. Olfersia americana (Leach), Aldrich, Catalogue of North American Diptera, p. 655. 
Previous Records. A widely distributed and often recorded species, 
infesting chiefly owls, in North America. Massonat (1909) has recorded the 
species from Platalea leucorodia in France, but, if we may rely upon his figures, 
his specimens represent an entirely distinct species. 
Specimens Examined. Numerous examples from California and from 
Washington, District Columbia, from various species of owls. 
Major Austen has very kindly compared one of our specimens with the 
type of this species in the British Museum and has confirmed this determination. 
Notes. The accompanying figure of the female (Fig. 11) should make the 
recognition of this species relatively easy. It is usually a reddish-brown species, 
some specimens being paler than others. The antennae are comparatively 
small and are strongly bristled at the apex. The frontalia is quite large and 
the orbits are wide. The section of horizontally striated membrane down the 
centre of the dorsum of the abdomen is quite noticeable. The chaetotaxy and 
form of the male are essentially the same as in the female. The male genitalia 
are characteristic, consisting mainly of two slender, pointed side pieces, 
possibly corresponding to the superior forceps, and a long central piece which 
is curved at the base, rather heavily chitinized and pointed. This may be 
