group because of the frequent appearance of the species, Bibio albipennis Say, in 
large numbers in March. Because of its huge numbers, Plecia nearctica Hardy, the 
lovebug, is a nuisance to drivers in the Gulf States. The larvae usually feed on 
decaying vegetable matter, but a few feed on the roots of grass and other plants. 
Family Sciaridae 
Darkwinged Fungus Gnats 
Darkwinged fungus gnats are moderately small, slender, delicate, mosquitolike 
insects. The antennae have 12 to 17 segments, the wings are large, the coxae are 
prominent and elongated, and the tibiae are armed with spurs. The adults are often 
common in dark, humid habitats in wooded areas. Many species breed on mush- 
rooms or on fungi growing on trees and logs. A number of others are predacious and 
are found under bark or in the galleries of wood-boring insects. 
Family Cecidomyiidae 
Gall Midges 
There are more than 1,000 described species of Nearctic cecidomyiids, of which 
several hundred are known to attack various trees and shrubs (430). The oaks are 
especially favored as hosts but several other species of trees are also infested, such 
as willow, elm, maple, walnut, hickory, and the pines. The larvae of about two- 
thirds of the species cause the formation of galls or pronounced swellings by their 
feeding (400). Others feed in such places as patches of pitch exuding from injured 
limbs, on fungi, in the excrement of insects, birds, and mammals, and in galls 
produced by other insects. A few are predators on small insects such as aphids, 
mites, psyllids, and scales. 
Gall midges are small, mosquitolike flies with relatively long antennae and legs. 
Young larvae are slender, somewhat flattened, and taper toward each end. Full- 
grown larvae are distinguished by the presence of a sclerotized structure, commonly 
known as a spatula, on the underside of the front end. 
The balsam gall midge, Paradiplosis tumifex Gagné, produces swollen, oval 
galls about 3 mm in diameter near the bases of needles of balsam fir (95/7). It most 
likely also occurs on Fraser fir and wherever these hosts are found in North 
America. Damage in Christmas tree plantations may be severe because galled 
needles drop from the twigs in October. 
Dasineura balsamicola (Lintner) originally was believed to be the cause of the 
gall formed by P. tumifex (482). However, the role played by D. balsamicola is that 
of inquiline, and this midge kills the gall-former P. tumifex where they occur 
together. Closer study of other species of Dasineura may reveal similar rela- 
tionships. D. gleditchiae (Osten Sacken), the honeylocust pod gall midge, pro- 
duces oblong, podlike galls on the new leaflets of honeylocust seedlings in nurser- 
ies in the Midwest, New England, Oregon, California, and Pennsylvania. D. 
pseudacaciae (Fitch) attacks the young leaves of black locust and causes them to 
fold, and D. communis Felt, the gouty vein midge, produces greenish or reddish 
pouch galls on the veins of the leaves of red and sugar maples. 
The boxwood leafminer, Monarthropalpus buxi (Laboulbene), an introduced 
species, occurs from Rhode Island south to Delaware and Maryland. Its hosts are 
different varieties of boxwood, the tree boxwood and the glossy leafed boxwood, in 
particular. Adults are orange-yellow and about 2.5 mm long. The larvae feed within 
the tissues of the leaf, causing blisterlike blotches up to 2.5 mm long by fall. 
Heavily infested leaves turn gray or yellowish brown and often drop prematurely. 
Contarinia juniperina Felt, the juniper midge, is a pest of redcedar and other 
junipers in the Midwest and California. Adults are very small, only about 1.5 mm 
long, and have bright-red abdomens. Eggs are laid on the needles of new growth 
442 
