154 NEMATTJS ABDOMINALIS. 



Nematus ventralis, Hart., Blattw., 192, 16 ; Costa, F. N., 15, 63, 



7 ; Evers., Bull. Mosc., xx, 14, 

 17; Thorns., Hym. Scand., i, 

 137, 66 ; Brischke, Beschr., 8, 

 pi. i,f.6(lar.); Kalt., Pfl., 320 

 (lar.). 



Graverihorsii, Gimm., Bull. Mosc., ix, 432. 



luteus, var. k. Thorns., Opus., 632, 41. 



Deep black, shining, sparsely covered with slight down ; the head 

 a little narrower than the thorax ; the apex of clypeus, labrum, a spot 

 behind each eye, tegulae and edge of pronotum, the abdomen except 

 the basal segment, and legs, reddish -yellow. The antennae are a little 

 shorter than the body, the apical half pale-brown beneath ; the third 

 and fourth joints are equal in length. Wings deep blackish ; lighter at 

 the apex ; the stigma deep reddish-yellow ; the basal half black ; the 

 third cubital cellule is nearly as long as the second. The coxse are black 

 at the base. 



The g has the last segment scarcely emarginate. Its dorsal surface 

 is either entirely black or only black at the base. 



Length 3 3^ lines. 



Ab. a. Tegulse and pronotum totally black. 



This common species is readily known from its 

 congeners by the deep black head and thorax, the 

 deep smoky wings with the long third cubital cellule, 

 and yellowish stigma with the basal half black. 



The larva has the head shining brownish-yellow, with 

 black eye-spots, and dark-coloured mouth organs. The 

 body is flat, with the segments distinctly separated, the 

 ground colour is yellowish-green, as are also the legs ; 

 the back is darker. On each segment are four rows 

 of white tubercles ; the segments at their juncture are 

 whitish. When young the head is lighter coloured ; 

 and the back dark bluish-green. 



The eggs, according to Brischke, are laid on the 

 slender green twigs in a row ; they are elliptical, white ; 

 and two days after being deposited a black crust forms 

 on the incision made for each egg. 



The larvae lie stretched flat on the underside of the 

 leaves of the alder and devour them between the 

 principal nerves. They are found very commonly 

 during August, September, and October. There seems 

 to be but one brood in Scotland, but possibly there 

 may be two in England, as is the case on the Con- 

 tinent. 



