CRABRO CETRATUS. 145 



flowers of Umbelliferae ; it has also been taken at Southend, and 

 Mr. S. Stevens took it in Devonshire. Very abundant at Pake- 

 field near Lowestoft, Suffolk, where great numbers were taken 

 settling on the leaves of the Coltsfoot. 



23. Crabro cetratus. 



C. niger ; tibiis scutelloque parvis, nigris, margine albo. 



Crabro cetratus, Shuck. Foss. Hym. 131. 4. 



Dahlb. Hym. Europ. i. 337. 221. 



Wesm. Hym. Foss. Belg. 133. 10. 

 Crabro dilatus, Herr. Schdff. Faun. Germ. 181. 54. 

 Crabro melanarius, Bold,Zool.xv. 5631. 



Female. Length 3 -4 lines. Black and shining ; the head with 

 very delicate shallow punctures; a deep longitudinal impression 

 extends from the anterior stemma to the base of the antennae ; 

 the clypeus densely covered with silvery pubescence, its margin 

 truncate at the apex ; the mandibles ferruginous at their apex 

 and bidentate ; the palpi very dark rufo-fuscous, nearly black. 

 Thorax very delicately punctured; the metathorax not having 

 the usual enclosed space at the base; a deep longitudinal 

 channel runs from the base to the apex, on each side of which 

 it is delicately obliquely rugose ; the femora and tibiae with a 

 fine changeable pile ; the posterior tibiae clavate, with a double 

 row of short, fine, acute spines outside ; the calcaria pale rufo- 

 testaceous, as well as the apex of the tibiae. Abdomen clavate, 

 the margins of the two basal segments slightly depressed ; the 

 apical segment compressed, margined at the sides, shining and 

 punctured, with the tip ferruginous. 



Male. Length 3^-4 lines. Black ; the head delicately punc- 

 tured, with an impressed line in front of the anterior stemma 

 extending to the sulcation of the face, another between the 

 stemmata extending a little behind the posterior ones; the 

 clypeus and inner orbits of the eyes covered with silvery pubes- 

 cence ; three or four of the basal joints o the flagellum fim- 

 briated beneath. Thorax : the angles of the prothorax rounded; 

 the mesothorax smooth, shining, and sparingly punctured ; the 

 metathorax gibbous, without a distinct enclosure at its base ; 

 having a central, longitudinal, consute incisure, and the lateral 

 lobes irregularly and delicately obliquely striated ; the anterior 

 tibiae and first joint of the tarsi dilated externally, with a pale 

 margin ; the calcaria of the posterior legs sometimes fuscous ; 

 the wings hyaline and iridescent, with the apical half faintly 

 clouded. Abdomen shining, the centre of the segments some- 

 what thickened, the apical one curved downwards. 



