1056 WaLter H. WELLHOUSE 
Tingitidae 
bellula Gibson, Corythucha (Plates LX XII and LX XIII) 
Although the original description of Corythucha bellula was published 
but recently (Gibson, 1918), the species seems to be fairly common where 
its host plants occur, and it has probably been confused with C. cydoniae 
by earlier observers who must have seen it on the hawthorns. It has 
been found by Drake in Ohio and by Criddle in Manitoba. 
The host plants include those species of Crataegus that have hairy leaf 
veins, and also Alnus incana and Ribes oxyacanthoides. The writer has found 
the insect breeding in abundance on Crataegus neofluvialis and to some 
extent on C. albicans and C. punctata. The hawthorns with smooth leaves, 
such as C. pruinosa, C. crus-galli, and C. oryacantha, even when their 
branches were intermingled with thos: of trees that were badly infested, 
revealed no nymphs nor eggs. 
In a large thicket of C. neofluvialis trees near the Cornell University 
campus, the leaves were so discolored by the end of July that they attracted 
attention several hundred yards away. By the middle of August the 
leaves were falling, and the branches were bare by September 1. No 
fruit matured on these trees. A few scattered trees of this species in other 
directions from the city were also badly infested. Individual trees of 
C. albicans and C. punctata showed an occasional branch badly infested 
and with leaves discolored. The injury is caused by the nymphs and 
the adults puncturing the under surface of the leaf and sucking the sap, 
producing at first a mottled effect due to the pale areas around the feeding 
punctures, while later the leaf turns brown and falls to the ground. Orna- 
mental plantings of Crataegus in parks and gardens are rendered unsightly 
and weakened by this injury. 
There are two generations annually at Ithaca. The first brood hatches 
in July from eggs laid in late May and in June, and the nymphs become 
mature in from twenty to twenty-five days. The second-brood eggs are 
laid in late July and in August, and the adults appear in late August and 
in September. 
The adults of the second brood hibernate among the fallen leaves and 
in crevices of the bark. Many of them remain’ on the leaves on which 
they were feeding before the leaves fell. They appeared the last of 
May, and during early June were feeding on the new Crataegus leaves. 
As a rule only one pair of adults was found on a leaf, and they remained 
feeding and ovipositing on that same leaf for several days. After emer- 
gence from the nymphal skin in September, the adults of the second brood 
continue feeding on the leaves until they fall, in late September or in 
October. 
The egg is subelliptical, with the basal end rounded and the apical end 
bent slightly to one side and capped with a rather broad cylindrical collar 
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