NEMATOCERA. 63 
wing.” Legs brown, shininf white underneath. Oviduct long and 
brownish yellow ; first segment flesh-coloured ; no valves. 
The larve live on Fraxinus excelsior, forming hollow elongated, 
pod-like aggregations, generally on the highest leaves. Before pup- 
ating they drop down to the earth and undergo their metamorphosis 
in the soil. The fly hatches in the spring. 
This species does not seem to have been figured; but has been 
described by Winnertz, Walker, Schiner, etc. 
C. betule, Wz. 
The larvee of this species pass the winter in the seed-capsules of 
the birch, Betula alba. They pupate in the same place. Some- 
times two pupz may lie side by side in the same capsule. The 
perfect insect commences to appear at the end of March and during 
April. 
The perfect insect is dusky yellow, with the top of the thorax 
black ; the abdomen also occasionally dark. Legs pale yellow. 
Antennz dark brown, 12 to 13 jointed in ¢, apical joint with a very 
shert petiole ; in the ? twelve sessile joints. Wings limpid ; trans- 
verse veinlet placed a short distance before the middle of the first . 
longitudinal vein ; second longitudinal nearly straight, joining the 
costa near the tip of the wing; the second branch of the third 
longitudinal bending round to the hind border. Halteres grayish- 
white. Third segment of oviduct white; no valves. 
We know of no figure of this species. The metamorphosis was 
made known by Loew. Described by Winnertz, p. 234, Lin. Ent. 
C. saliciperda, Duf. (the Willow Fly) 
C. albipennis, Lw. Wtz. Walker. 
= 1C. terebrans, Lw. 
Rhabdophaga viminalis,* Westwood. 
The orange-coloured larve of the willow-fly may be found from 
July to the following April in the wood of young willows, under the 
bark—chiefly Sa/ix alba, but also on poplars.t The ? lays chains 
of long yellow-coloured eggs. The larve dig out short, irregular 
passages, forming gall-shaped swellings, and causing the bark to 
become scabby and to crack and burst. Bergenstamm says “ Ver- 
wandlung daselbst”;{ but this does not always seem to be the case. 
The perfect insect is black, clothed with black hairs. The thorax 
is grayish, with four indistinct black bands; sides of the abdomen 
* Lin, Ent., 1851, p. 373: + Gard, Chron., 1847, p. 588. 
P 
$ Sy. Cecid., 70. 
