56 INSECTS AFFECTING DOMESTIC ANIMALS. 
parts of the face and neck, resulting from the repeated bites, which cause an intense 
irritation and even give rise to cutaneous sores. The inclination of the gnats to bite 
increases with the advance of the 
Season, but the pest is considera- 
bly abated after the fall of the 
water. They are also very trou- 
blesome to animals, and are sup- 
posed to cause the inflamed eyes in 
the horses of this region through 
the summer months. I append a 
description of the species. The 
female is alone described, as that 
is the only sex which composes the 
biting swarms, and I have not se- 
cured either the male or the early 
stages. 
Compared with other 
forms, Townsend says: 
This species is smaller than 
either S. pecuarum or S. meridionale. 
ft eae S. metallicum Bell , from Mexico, is 
given 'as 2 mm. long, but it is the 
Fig. 20.—Si ium piscicidium: a a; a - - : 
eS 20 imulium pis tetdium a, larva; b, pupa, dorsal male which is described, and the 
view; c, same, lateral view; d, same, ventral view; e, 
thoracic proleg; /, rows of bristles at end of body (from female would bevery much larger. 
American Entomologist). S. occidentale differs from S. 
pecuarum very markedly in the 
thoracic and abdominal markings. These markings are very much like those of S. 
meridionale; but the median thoracic line is always very faint, the abdomen is light 
fulvous, the lateral lines of segments 5, 6, and 7 are curved, and the abdominal mark- 
ings are of a different color, besides other minor differences. 
Simulium piscicidium Riley. 
The past history of this species, together with the important features 
of its life history, have already been stated in connection with the dis- 
cussion of the habits of the members of the family. 
It has been recorded from New York and Ohio, but further than this 
we are not informed as to its geographical limits. 
The eggs of this species have not been described, nor is it known 
where they are laid, or the details of the early life of the larva. The 
larger larve and their habits, to some extent, have been detailed and 
already referred to ‘The accompanying figures will serve to show the 
similarity to the other species, and we include them in order to bring 
together as much as possible the material which will be of service in 
the further study of the habits of the group. 
The adult described in the American Entomologist (Vol. II, p. 367) 
is for the most part velvety black, with a faint fulvous pubescence on 
the thorax, and the eyes and sides of the abdomen inclining to brown- 
ish or rufous. The length of the body in alcoholic specimens is 0.14 to 
0.17 of an inch. 
