146 Arthropods as Simple Carriers of Disease 
arranged in a longitudinal series and in addition two pairs 
of series of smaller processes (fig. 100) F. canicidaris 
bb. Male with blackish abdomen, middle tibia with a tubercle 
beyond the middle. The larva with spiniferous appen¬ 
dages of which the dorsal and ventral series are short, the 
lateral series long and feathered (fig. 101). . . .F.scalaris 
aa. Apical cell (R) of the wing more or less narrowed in the 
margin; i. e., the bounding veins more or less converging 
(fig. 108). 
b. The mouth-parts produced and pointed, fitted for piercing, 
c. Palpi much shorter than the proboscis; a brownish gray 
fly, its thorax with three rather broad whitish stripes; 
on each border of the middle stripe and on the mesal 
borders of the lateral stripes is a blackish brown line. 
Abdomen yellowish brown; on the second, third and 
fourth segments are three brown spots which may be 
faint or even absent. The larvae live in dung. The 
stable-fly (fig. no). Stomoxys calcitrans 
cc. Palpi nearly as long as the proboscis. Smaller species 
than the house-fly. The horn-fly (fig. 167) 
Hcematohia irritans 
bb. Mouth-parts blunt, fitted for lapping. 
c. Thorax, particularly on the sides and near the base of the 
wings with soft golden yellow hairs among the bristles. 
This fly is often found in the house in very early spring 
or even in the winter. The cluster-fly, Pollenia rudis 
cc. Thorax without golden yellow hairs among the bristles, 
d. The last segment of the vein M with an abrupt 
angle, (fig. 108). The larvae live in manure, 
etc.House-fly, Musca domestica 
dd. The last segment of vein M with a broad, gentle 
curve (fig. 102). 
e. Eyes microscopically hairy; each abdominal 
segment with two spots. Larvae in dung. 
Myiospila meditahunda 
ee. Eyes bare ; abdomen gray and brown marbled. 
Muscina 
f. With black legs and palpi. M. assimilis 
