THe InNSEcT FAUNA OF THE GENUS CRATAEGUS 1035 
pomi De Geer, Aphis (Green apple aphis) 
During June and July the succulent sprouts of European and native 
hawthorns are badly infested by green apple aphids. Whenever the weather 
becomes unfavorable for their enemies they increase rapidly and infest 
entire trees or hedges, but fair weather checks them again. 
prumfoliae Fitch, Rhopalosiphum (Apple bud aphis) 
The dark green stem mothers of the species Rhopalosiphum prunifoliae 
begin to appear on the buds of native hawthorns as soon as the bud scales 
have separated enough to show the green leaves within. The colonies 
increase during April and early May, doing some damage to the young 
leaves and buds, but before June they migrate from the trees to grasses 
and are not often found on the trees between early June and late autumn. 
The winter eggs are laid on hawthorn twigs and buds. 
Coccidae 
corni Bouché, Lecanium (European fruit lecanium) 
The species Lecanium corni is often very abundant on the lower side of 
branches of native hawthorns, and occasionally a branch is found to be 
almost entirely covered with these scales. Lower or inner branches that 
receive a scanty supply of ight appear to be killed by them. The young, 
flat scales are sometimes very plentiful on the leaves in late summer. 
furfura Fitch, Chionaspis (Scurfy scale) 
The flat, whitish scale known as Chionaspis furfura is very common and 
noticeable on the bark of all Crataegus species which the writer has 
observed. The small, elongate, white, male scales are often very abundant 
on the leaves and bark of Crataegus punctata. The injury caused by 
these scales is not noticeable. 
perniciosus Comst., Aspidiotus (San José scale) 
Although the San José scale is fairly common on all species at Ithaca, 
it does not seem to increase rapidly enough to become injurious. It is 
more commonly found on the smooth bark of young trees than on old, 
rough-barked trees. 5 
ulmi Linn., Lepidosaphes (Oyster-shell scale) 
The oyster-shell scale is common on the bark of native and European 
hawthorns, and a few badly infested branches have been found. Gen- 
erally, however, this species seems to be unimportant as a pest of Crataegus. 
vitis Linn., Pulvinaria (Cottony scale) 
The species Pulvinaria vitis is occasionally found on the twigs and 
branches of native hawthorns, but is not very abundant. 
