168 SPILOMENA TROGLODYTES. 



serted on each side of the base of the clypeus ; labrum con- 

 cealed; mandibles simple and arcuate (in the males, bidentate 

 at the apex). Thorax ovate ; the collar transverse ; the scu- 

 tellum transverse; the metathorax elongate and truncated; the 

 anterior wings with the stigma large and ovate, with one mar- 

 ginal and two submarginal cells, the first submarginal cell nearly 

 twice as large as the second, which is quadrate j the recurrent 

 nervure unites with the first transverso-cubital nervure', legs 

 simple. Abdomen subsessile, ovate-conic. 



1. Spilomena troglodytes. 

 S. niger ; pedibus piceis, tarsis posticis ferrugineis. 



Stigmus troglodytes, Van d. Lind. Obs. ii. 74. 2. 



St. Farg. Hym. iii. 99. 2. 

 Celia troglodytes, Shuck. Foss. Hym. 182. 1. 



Dahlb. Hym. Europ. i. 238. 139. 

 Spilomena troglodytes, Wesm. Hym. Foss. Belg. 123. 1. 



Female. Length If line. Black and shining ; the scape and 

 basal joint of the flagellum pale ferruginous ; these are some- 

 times black ; a carina runs up the middle of the face from the 

 base of the clypeus, halfway to the vertex, where it becomes 

 an impressed line, which extends to the anterior ocellus. 

 Thorax very delicately punctured; the collar longitudinally 

 striated ; the scutellum quadrate ; the superior surface of the 

 metathorax enclosed by a ridge round its margins; the en- 

 closure with two abbreviated longitudinal carinse in the centre, 

 the space between them transversely striated ; the wings hya- 

 line and iridescent, the stigma very large and black ; the ante- 

 rior tibiae, the apex of the intermediate pair, and all the tarsi, 

 ferruginous. Abdomen smooth and shining. 



Male. Length If line. Differs from the female in having the 

 clypeus very much produced ; the clypeus, a spot on each side, 

 the mandibles, scape, and basal joint of the flagellum, yellow ; 

 the legs usually pale rufo-testaceous, with the posterior femora 

 fuscous. 



This insect is only occasionally captured, usually by sweeping 

 herbage ; it is found about London, and appears to be pretty 

 generally distributed. I once took several specimens entering 

 burrows in a bank of very fine hard white sand, at Charlton, 

 Kent. 



