NYSSON DIMIDIATUS. 101 



5. Nysson dimidiatns. 



N. niger ; abdominis segmento primo rufo, et secundo utrinque 

 macula transversa alba signata. 



Nysson dimidiatus, Jurine, Hym. t. 10. f. 22. 



Oliv. Encycl. Meth. viii. 409. 9. 



Van d. Lind. Obs. ii. 33. 6. 



Shuck. Foss. Hym. 104. 5. 



Dahlb. Hym. Europ. i. 171. 105. 



St. Farg. Hym. iii. 49. 5. 



Wesm. Hym. Foss. Belg. 82. 6. 

 Nysson Wesmaeli, St. Farg. Hym. iii. 50. 6. 



Female. Length 3 lines. Black ; head punctured, the face with 

 a silvery pubescence ; the mandibles ferruginous. Thorax 

 shining and punctured ; the tubercles white ; an enclosed half- 

 circular space at the base of the metathorax, longitudinally 

 striated ; the sides of the upper surface of the metathorax 

 covered with silvery pubescence ; wings subhyaline, their apical 

 margins slightly clouded ; the anterior and intermediate tibia: 

 and tarsi and posterior tibiae at their base and apex, with some- 

 times a stain at the side, ferruginous ; the anterior tibiae with 

 usually a dark stain behind. Abdomen finely punctured, the 

 margins of the segments slightly constricted ; the first segment 

 and base of the second red, with a transverse white line on 

 each side of the second near the apical margin, and sometimes 

 a minute spot of the same colour on the third ; the margin of 

 the second and following segments obscurely rufo-fuscous. 



Var. /3. The second segment of the abdomen entirely red. 

 Var. y. The second segment of the abdomen black. 

 Var. d. The first segment of the abdomen with a yellow macula 

 on each side. 



The Male differs in having the face densely covered with silvery 

 pubescence; the apical joint of the antennae bi-emarginate 

 beneath ; the scape with usually a white stripe in front ; the 

 first segment of the abdomen has sometimes a white spot on 

 each side, and the third segment has frequently a narrow trans- 

 verse line on each side. 



This species is of rare occurrence, but it is widely distributed ; 

 it is taken in the London district at Hampstead and Highgate ; 

 it has also been taken at Weybridge and at Southend in July 

 and August, and on the sand-hills at Deal. When alarmed, it 

 feigns death and drops to the ground. 



