632. 

 PEMPHREDON UNICOLOR. 



Order Hymenoptera. Fam. Crabronidae. 



■ Type of the Genus, Pemphredon lugubris Fah. 



Pemphredon Lat., Fab., Vand. L., Curt. — Cemonus Jur. — Crabro 

 and Pelopoeus Fab. — Vespa Linn. 



Antennce inserted in front of the face, approximating, not so 

 long as the head and thorax, 13-jointed in the males (1), basal 

 joint long and stout, 2nd subglobose, 3rd nearly as long as the 

 Ist,^ the following decreasing in length and slightly tapering, 

 apical joint ovate-conic, more curved 12-jointed in the female. 

 Labrum inserted under the clypeus, horny, trigonate, all the 

 angles truncated, the anterior margin narrow and producing a 

 few long bristles (2). 



Mandibles crossing, elongated, broadest at the base, a little nar- 

 rowed at the middle, the apex rounded and quadridentate in the 

 female (3) ; forming 3 strong teeth in the male of P. unicolor. 

 Maxilla small, terminated by 2 lobes, the inner one small ovate 

 and ciliated internally, the outer one large subrhomboidal and 

 externally pubescent. Palpi long, pubescent on the inside, 5- 

 jbinted, basal joint the shortest clavate, 2 following nearly of 

 equal length, the stoutest, semilunate, 4th the longest, 2 follow- 

 ing a little shorter, 5th a little the slenderest (4). 

 Menium elongate-ovate, anterior margin bisinuated to receive 

 the Palpi, which are rather long, slender, internally pubescent 

 and 4 -jointed, basal joint long and clavate, the remainder short, 

 2nd and 3rd the stoutest, semilunate, 4th elliptical. Labium 

 transverse, cordate (5). 

 Head slightly transverse, a little broader than the thorax, subquadrate, 

 the angles rounded ; clypeus emarginate in the male, convex in the 

 female : eyes remote, ovate, placed obliquely at the anterior angles : 

 ocelli 3 in triangle on the crown. Thorax ovate : scutel transverse, 

 semiovate : metathorax gibbose. Abdomen not larger than the 

 thorax, slightly depressed, ovate-conic and attached by an elongated 

 strong petiole, slightly arched and narrowed at the base. Wings, 

 superior with 3 submarginal cells, \st long, 2nd subquadrate, each 

 receiving a recurrent nervure (9), or the \st receiving two, the Ind 

 none. Legs rather short, anterior a little the smallest : tibiae short 

 clavate, spurred at the apex : tarsi a little longer than the tibice, 

 slender and 5 -Jointed, basal joint elongated, 4th the smallest : claws 

 curved and acute. 



Unicolor FaJ., Lat. — Curt. Guide, Gen. 686. 4. — Sphex ater JFaJ. 

 In the Author's and other Cabinets. 



It would not be easy to jfind two groups so nearly allied, 

 that differ more essentially in the structure of their tropin, 

 than Pemp/iredofi and the species I have separated at folio 

 496 under the name of Diodontus, from the bidentate lahrum 

 of the type, which, it must be remembered, is the P. tristis of 

 Vander Linden, and is presumed to be synonymous with 

 Panzer's Psen pallipcs. D. minuttcs is also a typical species, 

 but for want of specimens for dissection I could not at the 



