CRABRO. 119 



This species is frequently to be found forming colonies in an 

 old post, rail, or decaying piece of timber. I have not detected 

 it with its prey. It is plentiful in the London district as well as 

 elsewhere. 



3. Trypoxylon attenuatum. 



T. nigrum ; antennis subclavatis ; abdomine clavato, segmento 

 primo elongato, attenuato. 



Trypoxylon attenuatum, Smith, Cat. Brit. Hym. Append. 120. 



Female. Length 3h lines. — Black ; the head opake, closely and 

 very finely punctured ; an impressed line extending from the 

 anterior ocellus to the apex of the prominence between the 

 antenna; ; the clypeus clothed with silvery pile, the palpi black. 

 Thorax subopake, the metathorax with a subenclosed space at 

 its base, evenly and divergently striated ; in the centre is an 

 impressed line which is continued beyond it to the apex of the 

 metathorax ; the wings beautifully iridescent, slightly clouded 

 at their apical margins. Abdomen : the margin of the first 

 segment much constricted, the two following slightly so, the 

 basal segment narrowed into a long petiole, as long as the two 

 following united, a longitudinal channel extending half its 

 length from the base. 



The Male only differs in having the antenna; more clavate with 

 the apical joint acuminate. 



This species has been bred from rose-sticks, into the pith of 

 which and similar plants it burrows; it has been found at Bristol 

 plentifully, and I have taken it in profusion at Reigate Common, 

 burrowing in the decaying wood of an outhouse. 



Genus 2. CRABRO. 



Sphex, pt., Linn. Faun. Suec. 411 (1761). 



Vespa, pt., Linn. Faun. Suec. 415 (1761). 



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



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



Rhopalum, Kirby, Steph. Syst. Cat. 366 (1829). 



Solenius, Blepharipus, Ceratocalus, Thyreopus, Crossocerus, Lin- 



denius, Corynopus, and Physoscelis, St. Farg. Ann. Soc. Ent. Fr. 



iii. (1834). 

 Entomognathus, Dahlb. Hym.Europ. i. 295 (1834). 



Head very large, subrotund or subquadrate, vertical in front ; 



