INSECT ENEMIES OF EASTERN FORESTS DT 
P. popult (Marlatt) and P. plesia Roh. on poplar, P. harringtoni 
(Marlatt) on willow, and the imported currant worm (P. ;rbesii 
(Scop.)) on currant and gooseberry. 
The records indicate that these species may have two complete 
generations or one and a partial second annually in the Northeast. 
It is possible that farther south some may have a partial third genera- 
tion. They pass the winter in the cocoon stage either in the duff on 
the ground or in the topsoil. The adults emerge early in the spring, 
usually over a period of 2 or 3 weeks, the dates depending somewhat 
on the climatic range and on the season. The larvae of the first gen- 
eration hatch out and begin to feed gregariously soon after the leaves 
of their food plant become fully expanded. Because of the extended 
period of adult emergence, there is an overlapping of generations, 
and larvae may be found from early in May until late in “September. 
The genus Pontania has many species and most of those of known 
habits are gall makers on willow and poplar, although a few are 
leaf folders and at least one species is known to infest the aments 
of willow. The adults are small, about 34, to 14 inch in length, and 
black or reddish yellow. The larvae are usually white or greenish 
white with black spots about the eyes, but in some species the head is 
faintly tinted with brownish. Some species of Pontania can probably 
be found throughout the entire range of the willows and poplars in 
North America. The gall- making species cause a leaf swelling 
(fig. 164), usually but not always globular. The galls are fleshy, 
project at least partially on both surfaces of the leaf, and are usually 
ereen, greenish yellow, or tinged with red. These galls result from 
the punctures made in the leaves by the female sawflies in laying 
their eggs, the wound closing and becoming invisible to the naked eye. 
The species that have been observed have one generation annually, 
and each larva feeds within the gall until full grown. Each species 
overwinters in a cocoon of delicate texture, which is usually con- 
Figure 164.—Galls of Pontaniau sp. on willow leaves. 
