174 BLACK-FLIES. 
Such tormenters are also exceedingly annoying in the 
northern part of Minnesota, and especially near Lake Su- 
perior. ‘‘Neither the love of the picturesque, however, nor 
the interests of science, could tempt us into the woods, so 
terrible were the black flies. This pest of flies which all the 
way hither had confined our ramblings on shore pretty 
closely to the rocks and the beach, and had been growing 
constantly worse and worse, here reached its climax. 
Although detained nearly two days, yet we could only sit 
with folded hands, or employ ourselves in arranging speci- 
mens, and such other occupations as could be pursued in 
camp, and under protection of a ‘“‘smudge-’? One, whom 
scientific ardor tempted a little way up the river in a canoe, 
after water plants, came back a frightful spectacle, with 
blood-red rings round his eyes, his face bloody and covered 
with punctures. The next morning his head and neck were 
swollen as if from an attack of erysipelas.”’ 
The above quotation, from ‘Lake Superior’? by Louis 
Agassiz, applies equally well today to the same locality, as 
experienced by such energetic entomologists as N. G. Hub- 
bard and E. A. Schwartz, who tried in vain to collect insects 
while black flies were out in force. 
Nor do such flies exist only in the north; they are as 
blood-thirsty in southern regions, and whoever has trav- 
eled in the tropics will have some very painful recollections 
of these pests, which are there usually called ‘“sand-flies.”’ In 
the southern part of the Mississippi Vailey cattle, horses, 
mules, and even fowls suffer terribly and many are killed 
outright. The common Buffalo Gnat (Stimulium meridionale 
Ril.) is a very large species which appears more or less sud- 
denly in large numbers, and as they-gorge themselves with 
the blood of animals, these soon succumb. ‘The loss of 
blood, together with the terrible irritation of the skin 
caused by the poison injected, is sufficient to kill in a very 
short time even such proverbially tough animals as the 
mule. All domesticated animals know this their worst 
enemy, and try to escape, but usually in vain, as the attack 
is always made very suddenly and unexpectedly. Farmers 
in the region infested by such gnats resort to smudges, 
