34 INSECTS AFFECTING DOMESTIC ANIMALS. 
Dr. Geza Horvath.! Its eggs, which are enveloped in a yellowish-white slime and 
deposited toward the end of May or beginning of June, are also deposited upon 
stones or grass over which the water flows 
and in the brooks of the more elevated 
regions. The female of that species is 
said to deposit on an average from 5,000 
to 10,000 eggs, but no detailed description 
is given, while we have found only about 
500 in the ovaries of our species. 
The larve are generally less than half 
an inch in length, subcylindrical, atten- 
uated in the middle, and enlarged toward 
both ends; the posterior third of the body 
is much stouter than the anterior third, 
and almost club-shaped. The color of the 
larva varies greatly, and is usually more 
or less like that of the substance upon 
whichit is fastened. The head, which is 
generally nearly square, is marked with a 
pair of small, black, approximate spots on 
each side that look like eyes, but are not. 
Beside the usual mouth organs, the head possesses two additional brown and fan- 
shaped bodies, which are usually spread out and kept in constant motion when 
catching food; they open and close like a fan, and if folded can be partially with- 
drawn into the mouth. The smooth body of the larva is composed of twelve joints 
or segments, five of which form the club-shaped anal portion of the 
body. On the under side of the thoracic portion is a subconical, 
retractile process (fig. 5), crowned with a circular row of short and 
sharp bristles. The anal extremity consists also of a subeylin- 
drical, truncated protuberance, which is crowned with rows of 
bristles similar to those of the thoracic proleg. The larva pos- 
sesses no stigmata, but immediately below the anal protuberance, 
on the under side of the body, there are three short, cylindrical, 
soft, curved, and retractile tentacles, to which the large trachewe 
lead, and which are probably the organs S. necunraes 
of respiration. Nie greatly en- 
In some of the most mature larve two larged (from 
kidney-shaped black spots are visible just Riley). 
above the thoracic proleg, one on each side. If closely 
investigated with a good lens, it is seen that the tufts of fila- 
ments serving the future pupa for respiration are already 
formed under the larval skin. All these filaments arise 
from the same spot and are branches of a single internal 
tube: “a7 
The most essential condition for the well-being of these 
aquatic creatures is rapid motion of the water in which they ~ 
live. * * * The nextimportant condition of a suitable 
breeding place is the presence of some stationary material 
* * * 
Fic. 4—Fan of Simulium pecuarum—gyreatly en- 
larged -(from Riley). 
Fic.5.—Proleg of 
a 
Fic. 6.—Breathing organs of in the water upon which to fasten themselves. 
8. meridionale—greatly en- Water in rapid motion is found only in certain, well- 
larged (from Riley). defined places, either in streams coming from an elevated 
plateau or in streams meandering through a level country. 
In the former any sudden bend, or declivity, and any obstruction, no matter how 
1A. Kolumb4esi légy, Dr. Horvath Géza, in Rovartani Lapok, Vol. I, No. 10, 
Budapest, 1884. 
