INSECT ENEMIES OF EASTERN FORESTS 529 
necessarily limit its use as a contre] measure. Experiments by Glas- 
gow (/88) indicate that the pyrethrum mosquito larvicide used in 
New Jer sey 1s highly effective for ridding a stream of blackfly larvae, 
and does little, if any, harm to fish. DDT can be used as a larvicide 
and as a protective spray on livestock. Temporary relief may be 
obtained by the use of the repellents described under mosquitoes. 
Famity TABANIDAE 
Horseflies, Deer Flies 
The horseflies are stout, bristleless flies with large eyes, and with 
the third antennal segment annulated and devoid of a style. Five 
posterior cells are always present, and the empodia are developed 
pulvilliform. 
The typical larva is elongate (fig. 128, #’), tapering at both ends. 
The head is small, with strong, downward- ‘pointed mandibles. Usually 
the abdominal segments are longitudinally striated and encircled with 
fleshy protuberances, as in 7’ abanus atratus. 
So far as known, ‘all the larvae of the Tabanidae are predaceous, 
except perhaps those of the genus Goniops. Most species are aquatic 
or semiaquatic, living in the mud beneath streams or in the sand 
along their borders. “Other species live in the soil beneath the leaf- 
mold. Leucotabanus annulatus (Say), the black horsefly (Zabanus 
atratus F.), 7. fulvulus Weid., and an unknown tabanid species have 
been recovered from wet, rotten logs and stumps. 
Because of the blood-sucking habits of the females, the adults of the 
genera Tabanus and Chrysops are serious pests of livestock and other 
animals. Species of CArysops, the banded-winged horseflies and 
deer flies, are among the most annoying of forest Diptera. They are 
active during the hottest weather, and will attack man furiously. 
The flies are particularly abundant following a rainy season, and 
control measures are ineffective. Animals may be best protected by 
darkened shelters, or the heads and bodies of work animals covered 
with nets. There is no satisfactory repellent. 
Famity HIPPOBOSCIDAE 
In the adult stage the Hippoboscidae are parasites on birds and 
mammals. They are flattened, louselike insects with apparently single- 
jointed antennae inserted in a depression. The legs are stout and 
broadly separated by the sternum. The claws are strong and often 
denticulated. A wingless species is found on sheep. The larvae 
develop to maturity within the parent and are deposited when they 
are about ready to pupate. 
The species are seldom seen except on their hosts. The sheep tick 
(Melophagus ovinus (li.)) is perhaps the best known representative 
of this family. Johnson (256) reported in 1925 that Lipoptena cervi 
(L.) has been taken from elk and deer; species of the genera Ornith- 
oica and Ornithomyia from small bir ds: Olfersia americana (Leach) 
from owls, the red-shouldered hawk, and the ruffed grouse; and 
O. fumipennis (Sahl.) from the bald eagle. 
