170 DIODONTUS MINUTUS. 



Found in the London district ; may be sometimes taken set- 

 tling on leaves of plants during hot sunny days in July and 

 August ; not very abundant. 



Genus 6. DIODONTUS. 



Crabro, pt., Fabr. Ent. Syst. ii. 293 (1793). 

 Pemphredon, pt., Fabr. Syst. Piez. p. 314 (1804). 

 Stignius, Lair. Gen. Crust, et Ins. iv. 84 (1806). 

 Cemonus, Jurine, llym. p. 214 (1807). 

 Diodontus, Ctirtis, Brit. Ent.W. 496 (1836). 



Head subquadrate, wider than the thorax; eyes lateral and 

 ovate ; ocelli in a triangle ; antenna? inserted at the base of the 

 clypeus, not approximated ; the clypeus transverse and triden- 

 tate ; the labrum produced and deeply emarginate ; the man- 

 dibles bidentate. Thorax ovate ; the metathorax obtusely 

 rounded ; the anterior wings with one marginal cell, acute at its 

 apex, and two submarginal cells ; the first oblong, receiving the 

 first recurrent nervure beyond the middle ; the second much nar- 

 rowed towards the marginal cell, receiving the second recurrent 

 nervure. Abdomen ovato-conical, attached to the thorax by a 

 very short petiole, the apex acute, in the male constricted into 

 an acute upcurved spine. 



The species of this genus may all be obtained in plenty by 

 collecting perforated rose-branches, or those of the common 

 Bramble; they provision their nests with Aphides; they also 

 burrow in sand-banks. 



1. Diodontus minutus. 



D. ater ; mandibulis nigris, basi et apice nigris ; tibiis anticis et 



intermediis pallide ferrugineis. 



Crabro minutus, Fabr. Ent. Syst. ii. 302. 32. 

 Pemphredon minutus, Fabr. Syst. Piez. 316. 9. 



Van d. Lind. Obs. ii. 78. 2. 



St. Farg. Hym. iii. 96. 2 ? (non $ ). 

 Sphex pallipes, Panz. Faun. Germ. 52. 22 ? 

 Cemonus minutus, Jurine, Hym. 214. 

 Stigmus minutus, Lair. Gen. Crust, et Ins. iv. 84. 

 Diodontus minutus. Curtis, Brit. Ent. fol. 496. 



Shuck. Foss. Hym. 185. 1. 



Dahlb. Hym. Europ. i. 252. 152. 



Warn. Hym. Foss. Belg. 121. 2. 



Female. Length 2 lines. — Black and shining ; the head deli- 



