NEMATOCERA. 63 



wing." Legs brown, shining white underneath. Oviduct long and 

 brownish yellow ; first segment flesh-coloured ; no valves. 



The larva; live on Fraxlniis iwcdsior^ 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. deiuhe, Wtz. 



The larvae of this species pass the winter in the seed-capsules of 

 the birch, Betula alba. They pupate in the same place. Some- 

 times two pupte 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. 

 Antennae dark brown, 12 to 13 jointed in ^, apical joint with a very 

 short petiole ; in the $ twelve sessile joints. Wings limpid ; trans- 

 verse veinlet placed a short distance before the nuddle 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. salicipcrda, Duf. (the Willow Fly) 



/ C. albipennis, Lw. Wtz. Walker. 

 = \C. terebrans., Lw. 



( Rhabdophaga viminalis,'^ Westwood. 



The orange-coloured larvae of the willow-fly may be found from 

 July to the following April in the wood of young willows, under the 

 bark — chiefly Salix alba, but also on poplars. f The ? lays chains 

 of long yellow-coloured eggs. The larva; 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. f Card. Chivn., 1847, p. 588. 



:;; Sy. Cecid., 70. 



