21 
This genus, as characterized above by Konow, 1 includes a group of 
small Nematines which, so far as their habits have been discovered, 
breed in galls on the leaves of various species of willow. So far as I 
am aware, all willow-leaf galls are caused by these insects. The Euuras, 
which come closest to them in habit, always produce galls in twigs or 
buds or inhabit twigs without resulting gall formations, and never 
attack the leaf proper. 
The European species, now known as Pontania gallicola Steph., is 
the type of the genus, and was described by Linnaeus in 1761 as Gynips 
caprece, evidently from the gall alone, and was referred to Gynips until 
1835, when the name Nematus gallicola was given it by Stephens, using 
Westwood's manuscript. The adult insect seems now for the first time 
to have been characterized. It was subsequently described by Ilartig 
as Nematus vallisncria (1837), and in 1859 the genus Pontania was 
erected for Ilartig's species by Costa. This genus was not very gener- 
ally adopted until revived by Konow. 
The habits of a number of our species have been detailed, notably by 
Mr. Walsh, 2 and particularly the hitter's species — pomum* pisum, and 
desmodioides. A quantity of material in various species has also been 
bred at the Department of Agriculture, and the habits of the genus 
based on these records may be brieily summarized, as follows: 
The galls, induced by the egg punctures of the females in young, ten- 
der leaves, begin to develop in early summer and are usually globular 
and fleshy and greenish in color, but later in the season frequently 
become rosy tinted or brownish. The larva reaches full growth early 
in the fall (September), and by this time has completely eaten out the 
interior of the gall, leaving it a mere shell filled with frass. The gall 
is almost invariably abandoned at this time by the larva, and the species 
studied at the Department seem to prefer to enter soft or rotting wood 
or the pith of plants to construct their hibernating cocoons. In the 
absence of such material they will form cocoons in the earth, and if 
supplied with neither earth nor wood they will sometimes hibernate 
within their own galls or enter others of their own species or of other 
insects. Pupation and transformation to the adult take place in the 
early part of March and during April, extending into May. Indoors, 
in breeding cages, where they are subject to unnatural conditions, they 
may issue as early as February, but this is exceptional. 
Mr. F. H. Chittenden, who has reared a number of these insects from 
cocoons in dead wood of maple, says of the adults (males of Pontania 
pisum) that they are extremely active and pugnacious. " Confined in a 
small vial, they began to fight at once, and when separated but a single 
specimen issued from the melee in perfect condition, the remainder 
being minus antennae and legs." 
1 Deutsche Entom. Zeitschrift, 1890, p. 237. 
2 See Proc. Ent. Soc. Pnila., VI, pp. 248-264; Am. Entom., vol. n, pp. 45-50. 
3 The cumbersome and uunecessary term salicis has been omitted in the case of this 
and the other species to which it has hitherto been prefixed. 
