66 THE ENTOMOLOGIST. 



Crabro ambiguus, Dalhbom. 



It is now a rare occurrence to have the pleasure of making 

 known the capture of a new British species of Aculeata ; but 

 a species of the genus Crabro, new to the fauna of this 

 country, has been taken by Mr. Vincent R. Perkins, That 

 gentleman submitted to me, for inspection, a box of small 

 species of Hymenoplera : among them I found four speci- 

 mens that I could not refer to any described in my work on 

 these insects. The specimens were males, and belonged to 

 the division in which that sex has dilated anterior tarsi. I 

 could not find the species described either in Van der 

 Linden's work on the Fossores, or in that of St. Fargeau ; 

 but at last 1 discovered it to be described by Dalhbom in his 

 ' Hymenoptera Europa^a.' It is that author's Crabro ambiguus. 

 The specimen may be recognised by the male having the 

 anterior tibial clavate, and the first joint of the tarsi broadly 

 expanded, outwardly convex, and having three black spots on 

 it ; the second joint is small, broader than long, and has a 

 minute black spot in the middle of its apical margin. I give 

 descriptions of both sexes, that of the female being compiled 

 from Dahlbom's work. 



Male. — Length 21 lines. Black, smooth, and shining; 

 the head narrowed behind the eyes; the posterior margin of 

 the vertex acutely margined, terminating laterally in an acute 

 angle or tooth ; the ocelli in an equilateral triangle on the 

 vertex ; at the sides of the posterior pair, an oblique fossulet, 

 that extends to the margin of the eyes ; in front of the 

 anterior ocellus, a deep, longitudinal, impressed line, runs to 

 the insertion of the antennae ; the clypeus covered with 

 silvery pubescence ; the mandibles black, longitudinally 

 channelled, with two acute teeth at their apex, which is 

 rufo-piceous ; the antennag black. Thorax, above, shining; 

 the enclosed space at the base of the metathorax smooth and 

 shining, having a deep longitudinal channel, and a few 

 oblique striae at its base ; the metathorax is transversely 

 striated posteriorly ; the anterior tibiae clavate, yellow in 

 front and at the apex ; the tarsi white ; the first joint flattened 

 and broadly dilated, straight in front and rounded behind; 

 convex outwardly, and having three black spots; the second 

 joint small, cordate, and with a minute black spot in the 



