104 
Parasitic Arthropoda 
accomplished by spraying kerosene oil on the surface of the water, or 
by the introduction of fish which will feed on the larvas. 
Detailed consideration of the 
most efficient measures for con¬ 
trolling mosquitoes is to be found 
in Dr. Howard’s Bulletin No. 88 
of the Bureau of Entomology, 
“Preventive and remedial work 
against mosquitoes” or, in more 
summarized form, in Farmers’ 
Bulletin No. 444. One of these 
should be obtained by any person 
interested in the problems of mos¬ 
quito control and public health. 
The Simuliidae, or Black Flies 
The Simuliidae, or black flies, are small, dark, or black flies, with 
a stout body and a hump-back appearance. The 
antennae are short but eleven-segmented, the wings 
broad, without scales or hairs, and with the anterior 
veins stout but the others very weak. The mouth- 
parts (fig. 74) are fitted for biting. 
The larvae of the Simuliidae (fig. 75) are aquatic 
and, unlike those of mosquitoes, require a well aerated, 
or swiftly running water. Here they attach to stones, 
logs, or vegetation and feed upon various micro¬ 
organisms. They pupate in silken cocoons open at 
the top. Detailed life-histories have not been worked 
out for most of the species. We shall consider as 
typical that of Simulium pictipes, an inoffensive 
species widely distributed in the Eastern United 
States, which has been studied especially at Ithaca, 
N.Y. (Johannsen, 1903). 
The eggs are deposited in a compact yellowish layer 
on the surface of rock, on the brinks of falls and 
rapids where the water is flowing swiftly. They are 75 Larva of Simu _ 
elongate ellipsoidal in shape, about .4 by .18 mm. AfteH^'rmam 
As myriads of females deposit in the same place the 
egg patches may be conspicuous coatings of a foot or much more 
in diameter. When first laid they are enveloped in a yellowish 
74. Mouth parts of Simulium. After 
Grunberg. 
