The Two-winged Flies 
345 
pharynx, causing terrible pain and sometimes death. Indeed, out of twelve 
cases which came to the knowledge of Dr. Richardson, an Iowa physician, 
eleven resulted fatally. As many as three hundred screw-worms were taken 
from the- inner nose and region above and behind the soft palate of some 
of the patients. As a pest of domestic animals the greatest injuries have been 
caused in Texas. The eggs are laid in any open wound or in the nose or mouth, 
and the quickly hatching larvae burrow into the adjacent tissues. Cattle and 
hogs are particularly attacked, horses and sheep less often. 
In the states in which sugar-beets are grown some anxiety for the success 
of this new industry—new in this country, that is; sugar has long been made 
from beets in Germany—is felt because of the presence in the beet-fields 
of an obscure little fly, Pegomyia vicina, which may be called the sugar-beet 
midge. The eggs are laid on the leaves, and in three or four days the tiny 
white larvae hatch and burrow into the soft leaf-tissue. When many of the 
larvae are at work mining the leaves much injury to the plants results. In the 
great sugar-beet fields along the California coast four or five generations 
of this fly appear annually and occasion great loss to the growers. This 
fly belongs to the subfamily Anthomyiinae, to which Muscid group two 
other well-known fly-pests belong, namely, the onion-fly, Phorbia ceparum , 
and the cabbage maggot-fly, Phorbia brassicce. Both these insects in the 
adult stage are small light-gray flies, looking rather like small house-flies. 
The onion-fly lays its eggs on the stems of onion-plants, near the soil, and 
the hatching larvae burrow into the underground bulb, which they soon 
nearly destroy. This fly appears to live on no other plant. The cabbage 
maggot-fly lays its eggs also on the stem just above or even below the ground, 
and the larvae burrow into the roots. Cauliflowers as well as cabbages 
are attacked, and often tens of thousands of acres of these two vegetables 
are destroyed in a single season by this little fly. The best remedy is the 
use of cards cut from tarred paper and bound, collar-like, around the stems 
of the plants. These protecting collars should be put on when the young 
plants are transplanted from the cold frames into the field. Another familiar 
member of this subfamily is the little house-fly, Homalomyia canicularis , 
smaller, paler, and more conical in shape than the true house-fly. 
Evfery one who has undertaken to rear butterflies and moths from their 
caterpillars has been compelled to make the acquaintance of certain heavy¬ 
bodied bristly flies which appear now and then from a cocoon or chrysalid 
in place of the expected moth or butterfly. These are Tachina-flies, and in 
their appearance and parasitic habits are representative of the large sub¬ 
family of house-fly cousins known as Tachiniinae. The females fasten their 
eggs to the skin of young caterpillars, the hatching larvae burrow into the 
body of their crawling host and feed on its body-tissues. Sometimes the 
caterpillar is killed before it can pupate, but usually not, spinning its cocoon 
