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DIPTERA. ‘49 
the houses in villages and cities, and the windows are frequently completely cov- 
ered with them. 
MODE OF ATTACK. 
The flight of all species of Simulium is very swift and powerful. They possess, in 
comparison with most other flies, an enormously large thorax, consisting of a very 
tough, chitinous integument, that furnishes ample attachment for the strong muscles 
which propel them during their long and continuous flights. 
The Southern buffalo-gnat is exceedingly active in all its motions, and is at its 
bloody work as soon as it has gained a foothold upon an animal> The individual 
flight is inconspicuous and rarely more than a few feet from the ground. It is also 
usually noiseless, but when one passes rapidly close to the ear of a person the sound 
produced is faintly like that of a passing bullet, and no one who has listened to it 
will ever forget it, but will always connect it with their presence. 
If the insects are not very hungry, orif influenced by too warm or too dry an 
atmosphere, they circle round a mule or a horse very much like so many small bees; 
if hungry, however, they lose no time whatever, but with a few nervous jerks settle 
upon the selected spots and immediately go to work. They are never quiet, but are 
most active during early morning and toward evening. They also fly during moon- 
light nights. During the hottest portions of the day, from 11 a. m. to 4 p. m., they 
are more or less inactive. Their favorite time of attack is a cloudy, dark day, or 
when rain is threatening. If the gnats try to enter houses or stables by means of 
the windows, they constantly butt their heads against the panes of glass, until they 
become so exhausted that they drop to the ground and die. Specimens kept in con- 
finement in large vessels, with the bottoms covered with moss and soil and contain- 
ing a wet sponge and a saucer filled with water, die within forty hours. During all 
this time they never cease trying to escape. The sense of smell (and sight) of these 
insects must be well developed, because they unerringly find animals a long distance 
away from their breeding places. If very numerous they cover the whole animal, 
without making any selection of position. 
The smaller turkey-gnats are nof so bloodthirsty, nor do they form such large 
swarms. The snorting, biting, switching of tails, and the general restlessness of the 
stock in the fields soon reveal the presence of their foes. The gnats will, upon 
arrival, rapidly circle around the animal, select a point of attack, fasten themselves 
upon the chosen spot, and immediately commence to bite. The genital and anal 
regions, the ears and portions of body between the forelegs—in short, those parts 
where the skin is most easily punctured—are selected by these insects. The attack 
is so rapid that in course of one minute the body of the tormentor is seen to expand 
with blood, which shows plainly through the epidermis of the abdomen. The bitten 
part of the animal shows a nipple-like projection, and if the insect is removed by 
force a drop of blood as large as a good-sized pin’s head will ooze out. Other gnats 
will almost at once pounce upon the same spot and continue the biting. All those 
veins which project under the skin of the animal are also favorable points of attack, 
and their course is made visible by the hordes of gnats fastened upon them. 
REMEDIES TRIED AND PROPOSED AGAINST THE LARV. 
The results of a number of different experiments with insecticides upon the larve 
of the buffalo-gnats made by Mr. Lugger during the early spring indicate that it is 
nearly if not quite impossible to reduce their numbers by killing them in the streams, 
To attempt to do so when all these streams are swollen, and frequently from 10 to 20 
yards wide and half as deep, would be sheer waste of time. When the water is very 
low and much more sluggish in its motion, thus bringing the chemicals in contact 
with the larve, an application of them might be more effective. Great caution 
must be used in any efforts in this direction, however, as both man and beast are in» 
4653—No. 5—4 
