304 



Insect Pests. 



Eetz. ; Nematus septentrioncdis, Olivier; Ncmatus laticrux, Villaret ; 

 Croesus scptcntrionalis, Leach ; Crcssus laticrux, Stephens. 



LIFE-HISTORY AND HABITS. 



The sawfly appears in May and June, usually at the beginning 

 of the latter month. 



It varies in length from a little less to slightly more than ^ inch. 

 In colour it is black, shiny and covered with dense pubescence ; the 



FIG. 204A. THE NUT SAWFLY (Ci 



ptentrionalis. Linn.). A, adult ; B, larva;. 



abdomen has the two basal and two or three apical segments black, 

 the rest brick-dust red. The legs are peculiar, the posterior pair 

 being long, the apex of the tibia? being dilated, flattened and hollowed 

 on the inner side, metatarsus also dilated and flattened on the upper 

 side (which is curved), and the metatarsus is much longer than all 

 the other segments put together ; the second segment is as long as 

 the two succeeding. In colour the legs are black, the coxa; and 

 trochanters white, also the base of the hind femora, anterior tibia? and 

 tarsi, and half the posterior tibia? mainly white ; the apex of the 

 anterior femora brown beneath, anterior tibia? and tarsi reddish at 

 the apex, base of mid tarsi reddish. 



The male differs from the female in having the femora red, the 

 apex of the posterior femora black above ; mouth and tegulse reddish. 

 The femora are often jet black. Wings hyaline, but coloured on part 



