1939] 
Notes on Hippoboscidae 
71 
metrical methods. My material is not extensive enough 
for the purpose. Considering only the chetotaxy of the 
scutellum, this sclerite in Hippobosca bears at the extreme 
apical margin and somewhat ventrally a dense fringe of 
short, soft hairs. Anterior to the fringe one finds groups 
or rows of long, stiff bristles, either black or pale-colored, 
which I shall call the preapical bristles. The groups may be 
either far apart and restricted to the extreme sides or more 
or less connected medially. In some species the bristles are 
placed in one row, in others they form two irregular rows or 
are merely bunched together. When there are many 
bristles, these are often mixed with a few soft, short hairs, 
sometimes forming a second row behind the stiff bristles. 
In most cases the number and arrangement of the preapical 
bristles is the same in both sexes. There are two exceptions. 
In H. struthionis the males have more bristles on the aver- 
age than the females. In the males of H. camelina the pre- 
apical bristles occupy the same position as in the other spe- 
cies of the genus ; but in the females, the bristles are placed 
nearer the middle, being rather discal or medio-scutellar, 
and are also fewer in number than in the males. Except for 
this case of the female H. camelina, there are no discal nor 
basal bristles, setae or hairs on the scutellum in Hippobosca. 
The variation of the preapical bristles of the scutellum is 
discussed under each species, but the following summary 
compares the species for diagnostic purposes. The number 
of specimens examined is given in parenthesis. 
equina (106) : 5 to 11 bristles $ $ (average, 7). 
longipennis (143) : 3 to 7 bristles $ $ (average, 5). 
fulva (3) : 8 bristles $ $ . 
variegata (95) : 13 to 27 bristles $ $ (average, 18). 
rufipes (95) : 12 to 23 bristles $ $ (average, 17). 
hirsuta (6) : 14 to 18 bristles $ $ . 
martinaglia ( not seen ) . 
struthionis (23) : 4 to 12 b. $ (average, 6) ; 8 to 15 b. $ 
(average, 10). 
camelina (31) : 3 to 8 b. $ (average, 5) ; 11 to 22 b. $ 
(average, 14). 
In Hippobosca, the integument of the abdomen, behind the 
usual large tergal and small sternal sclerotized basal plates, 
is mostly soft and extensible. All species I have seen have 
