others have been found feeding in the seeds and cones of conifers. 
Adults of the genus Hippelates are attracted to the eyes of man 
and animals and are very annoying. Certain species are also re- 
ported to transmit yaws and pinkeye. Gauraz apicalis Mall., Osci- 
nella coxendix (Fitch), Madiza glabra Fall., and Hippelates sp. 
have been reared from the leaders of white pine infested by the 
white pine weevil (467). 
FAMILY AGROMYZIDAE 
LEAF MINER FLIES 
These flies are very small and light or dark colored. The body 
covering ranges from sparse bristles to dense hairs. The larvae 
are plant feeders; some mine the cambium, but the majority mine 
the leaves. Frick (270) published a synopsis of North American 
species. 
Larvae of the genus Phytobia Lioy feed in the cambium of 
living trees, making long, thin, gradually widening mines (fig. 
170). These mines sometimes originate in the top of the tree and 
extend all the way to the base and into the roots. They cause 
defects known as pith-ray flecks. Heavily infested logs may be 
rendered unfit for some uses. 
Phytobia setosa (Loew) attacks red and sugar maples (320). 
Adults are small and dark colored. The larvae are opaque-white 
and about 16 mm. long. P. pruinosa (Coq.) infests wild cherry, 
maple, and black and river birches. Adults are about 3 to 4 mm. 
long; the larvae are up to 30 mm. long. This species apparently 
lays its eggs in the forks of branches near the tops of trees and 
the larvae tunnel all the way down into the roots. P. amelanchieris 
(Greene) attacks shadbush and P. pruni (Gross.), wild cherry. 
The holly leaf miner, Phytomyza ilicicola Loew, is a serious pest 
of American holly in eastern United States. The adult is a small, 
grayish-black fly about 25 mm. long. The female punctures leaves 
with her ovipositor and feeds on the juices exuding from the 
wounds. She also deposits eggs in the undersurfaces of leaves in 
F-506078, F-506069 
FIGURE 170.—Cambium miner work: Left, streaklike, longitudinal mines on 
trunk and roots of infested trees; right, “pitch-fieck’”’ defects in the wood. 
426 
