INSECT ENEMIES OF EASTERN FORESTS 525 
country Phoroctenia angustipennis (Loew) is recorded as damaging 
prune trees in Oregon. In Europe several species are reported as 
injurious to deciduous and coniferous plants. 
The larvae of Tipula abdominalis Say live under stones in brook 
beds and beneath saturated decaying leaves or clumps of grass adja- 
cent to water. This is one of the large species of 77pula, and because 
of its abundance and value as fish bait is much sought after by fisher- 
men. Alexander (7) listed species of the genera Limonia (Dicrano- 
myia and Rhipidia), Tipula, and others as occurring in decaying 
wood just beneath the bark, and Z’anyptera species in nearly solid © 
wood. Johannsen (254) in 1909 bred Phoroctenia apicata (O. 8.) 
from decayed elm. 
Of peculiar interest is Chionea valga Harr., the wingless snow- 
midge, whose midwinter appearance is frequently the cause of inquiry. 
These spiderlike creatures may be often observed walking awkwardly 
over the snow, even when the temperature is below freezing. They are 
of no economic importance. 
The family Sylvicolidae (Rhyphidae, Anisopodidae, Phryneidae), 
sometimes called the “false crane flies,” consists of only three genera, 
the adults of which are of a more or less diverse structure. The larvae 
have the abdominal segments divided transversely, as in the Therevi- 
dae. Mycetobia divergens Wlky. (fig. 128, C) has been bred from rot- 
ting wood and has also been found in the flowing sap of an elm tree. 
M. persicae (Riley) has been bred from gum and frass taken from the 
base of peach trees infested by borers. 
Famitry CHLOROPIDAE 
Frit Flies 
The frit flies are small, bare flies with hemispherical heads charac- 
terized by a large frontal triangle and usually short antennae. The 
auxiliary vein is vestigial, and the second basal cell is confluent with 
the discal cell. 
Parker (328) described the larva of Chloropisca glabra Meig. as 
elongate, about 6.5 mm. in length. From its greatest width of 0.7 mm. 
the body tapers to 0.5 mm. at the posterior end and to 0.2 mm. at the 
anterior end; it is sharply truncated posteriorly, and the segmenta- 
tion is indistinct. The posterior spiracles of the third instar are 
prominent, each with three spiracular openings, and the anterior 
spiracles slightly raised and seven-branched. The tracheal trunks 
are readily seen through the body wall. Most of the species are 
phytophagous, the larvae feeding on grasses, cereal crops, and. other 
plants. 
Siphonella inquilina Coq. has been bred from buttonbush twigs. In 
the West, Essig (745) reported Oscinis sulphurhalterata End. and 
Oscinella conicola (Greene) as having been bred from the cones of low- 
land fir, Abies grandis. Chlorops spp. and Oscinella spp. have been 
bred from dead hickory. 
Chloropisca glabra is predaceous on the sugar-beet louse. Gaurax 
anchora Loew. Pseudogaurax signatus (Loew), and Madiza oscinina 
Fall. are probably scavengers. The last two species have, however, 
been bred from spider egg sacs and may be predaceous at times G. 
apicalis Mall., Oscinella covendix (Fitch), M. glabra Fall., and Hip- 
