by the larvae produces a slimy condition which causes the husks 
to turn black, stick to and stain the shell. Nuts with damaged 
shells cannot be sold even though the contents are sound. The 
wings of the adult are transparent with dark cross-bars. Toxotry- 
pana curvicauda Gerstacker breeds in papaya in Florida and 
Texas. 
FAMILY CHAMAEMYIIDAE 
The larvae of a number of species in several genera of these 
small, grayish flies are predators of aphids, scale insects, and 
mealybugs. One species, Leucopis obscura Hal., a native of 
Europe, was introduced into Canada against the balsam woolly 
aphid in the early thirties. It quickly became established and, fol- 
lowing additional colonizations, spread over most of the infested 
areas in eastern Canada and into northern New England. Since 
1954, colonies have been released in aphid-infested stands in Ver- 
mont, New Hampshire, New York, and North Carolina, and the 
Pacific Northwest. It is usually found on heavily infested trees 
only, where it feeds mostly on adults that have laid many eggs. 
Cremifania nigrocellulata Cz., another European species, also 
imported into eastern Canada and the Pacific Northwest against 
the balsam woolly aphid, is now established. A fairly large 
number have developed on stem-infested trees, but their spread 
has been very slow. 
FAMILY LONCHAEIDAE 
Adults of this family are shiny black and about 5 to 6 mm. 
long. The larvae are very small and are covered by minute spines. 
These flies act mostly as scavengers or as predators on other in- 
sects. Lonchaea polita Say has been reared from bark-beetle in- 
fested wood. L. corticis Taylor has been recorded as an important 
parasite of the white pine weevil (467). 
FAMILY DROSOPHILIDAE 
VINEGAR FLIES 
These are the flies that are so often seen around spoiled fruit, 
slime fluxes, and fungi. Usually yellowish except for black mark- 
ings on the abdomen, adults seldom exceed 5 mm. in length. Few 
if any species are of importance as enemies of forest, shade, or 
ornamental trees. There is a possibility, however, that certain 
species are involved in the transmission of the oak wilt fungus, 
Chalara quercina (315). 
FAMILY CHLOROPIDAE 
CHLOROPID FLIES 
These flies are small to very small and bare to nearly bare in- 
sects. Some species are brightly colored with yellow and black. 
The larvae of certain species parasitize or prey on other insects; 
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