leaf petioles and either a bud or a part of the stem near the bases 
of the petioles (782). Damaged leaves fall prematurely and buds 
and branches are killed. Trees from 2 to 30 feet tall are attacked. 
The younger ones are often badly deformed. The related species, 
O. betulae (Winn.) feeds on and destroys the seeds of beech. 
The willow beaked-gall midge, Mayetiola rigidae (O.S.), pro- 
duces apical, beaked galls on the lower branches of many species 
of willow (fig. 168). In Michigan, eggs are laid singly on or near 
the buds of the host. Newly-hatched larvae penetrate the bud and 
a gall begins to develop by the end of the first larval instar and 
continues to enlarge until fall. Winter is spent as a larva inside 
the gall, and pupation occurs in the spring. The gall deforms the 
stem and occasionally a galled branch dies or breaks off (781). 
Many other species of gall midges have been recorded attacking 
various species of eastern trees. A few of the more common ones 
are as follows: Parallelodiplosis florida (Felt)—produces elon- 
gate, pocketlike swellings on the veins and midribs of scrub and 
pin oak leaves; Obolodiplosis robiniae (Hald.)—causes the mar- 
gins of black locust leaves to fold; Caryomyia holotricha (O. S.), 
C. sanguinolenta (O. S.), and C. tubicola (O. S.)—produce galls 
on hickory; Cincticornia pilulae (Beut.)—produces subglobose or 
globose, irregular, wrinkled, reddish galls on red oak leaves; 
Janetiella coloradensis Felt—causes swellings at the bases of 
serub pine needles; Prodiplosis morrist Gagne—feeds on the 
F-519914 
FIGURE 168.—Gall produced on 
willow by the willow beaked-gall 
midge, Mayetiola rigidae. 
F-519915 
FIGURE 167.—Damage to paper 
birch by the cecidomyid, Oligo- 
trophus papyrifera. 
420 
