1939] 
Notes on Hippoboscidae 
77 
Libya : Dernah (Klaptocz) . — Tunis : Gabes (Mik) . — Al- 
geria: Hamman Rirha; Hamman Meskoutine; El Kantara; 
Biskra (W. Rothschild and E. Hartert). — Morocco: 
Aguelman Sidi Ali bu Mohammed, Middle Atlas, 6,500 ft. 
(K. Chapman and J. W. S. Pringle) ; Ijoukak, Great Atlas, 
3,900 ft. (K. H. Chapman and G. A. Bisset) ; Arround, 
Atlas, 1,950 m. (Ebner). — Australia: Sydney, on a horse 
imported from New Caledonia. — New Hebrides: Tanna Id. 
(E. Robertson) ; Vila, Efate (or Sandwich) Id., very com- 
mon on horses (P. A. Buxton) . — Philippines : Alabang, 
Rizal (M. B. Mitzmain) . — Amboyna, off cattle (F. Muir) . 
— Singapore (F. Muir) . 
The preapical bristles of the scutellum vary from 5 to 11 
in 106 specimens examined (58 9 and 48 $), from 22 lo- 
calities, 85 specimens having from 6 to 8 bristles. The 
specimens fall in the following groups: with 5 bristles: 
3 (1 9,2 $ ) ; 6b. : 28 (17 9,11 $ ) ; 7b. : 22 (9 9 , 13 a ) ; 
8b. : 35 (24 9,11 a ) ; 9b. : 10 (4 9,6 a ) ; 10b. : 7 (3 9,4 
$ ) ; lib. : 1 ( $ ). There is no evidence of any sexual dif- 
ference in this character. No locality is represented by 
enough specimens to make a further analysis of any sig- 
nificance. The bristles are evenly divided between both 
sides in 69 specimens, unevenly in 37, the uneven groupings 
observed being 2 + 3, 3 + 4, 3 + 5, 4 4- 5, and 5 + 6. 
The frons, in the male, is nearly parallel-sided and about 
as wide as an eye; in the female it is slightly widened me- 
dially, where it measures a little over the width of an eye. 
In addition to the average larger number of preapical 
bristles of the scutellum, H. equina differs also from H. 
longipennis in the shape of the tergal plates of the abdomen. 
In the female of H. equina , the three median, setulose ter- 
gal plates are larger than in the female of longipennis , more 
transverse and ribbon-shaped, the median plate only slight- 
ly smaller than the hindmost plate, which is nearly as large 
as the anterior pair of subapical (lateral) plates. The 
median plates bear many more setae than in longipennis. 
In the male of equina , the three median tergal plates are 
large and ribbon-like, the hindmost (or third) plate fused 
with the anterior pair of ovate, widened subapical (lateral) 
plates (bearing longer bristles than the median plate 
proper). The shape and arrangement of the tergal plates 
