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656. 

 RHOPALUM TIBIALE. 



Order Hymenoptera. Fam. CrabronicIjE. 



Type of the Genus, Crabro rufiventris Panz. 



Rhopalum Kirb., Curt. — Physoscelus, Corynopus St. Farg. — Pem- 

 phredoni^ft^. — Crabro Fab., Panz., Vand. L., Shuc. 

 Antenna inserted at the base of the clypeus, approximating-, 

 scarcely longer than the head, geniculated, curved and simple at 

 the apex; 13-jointedin the male (1), basal joint long and stout, 

 2nd ovate, 3rd the same length but truncated, the remainder 

 quadrate, excepting the 6th joint which is oblong, emarginate 

 beneath, and the terminal one which is elongate-conic : 12- 

 jointed in the female, the 4th joint longer than the 3rd. 

 Labrum concealed beneath the clypeus, minute, transverse, the 

 sides rounded, anterior margin convex and ciliated with strong- 

 bristles (2). 



Mandibles rather long slender and cun'ed, crossing over the 

 labrum, hairy, broad at the apex and cleft, forming 2 trigonate 

 teeth, equal in the male (3). 



Maxillce terminated by an inflected lobe, hairy outside. Palpi 

 not long, pubescent, 5 -jointed, basal joint minute, 3 following 

 stout somewhat obovate, 4th longer than the preceding, but 

 shorter than the terminal joint, which is slender and subfusiform 

 (4). 



Mentum elongate- trigonate, the anterior margin waved. Labium 

 very short and concealed behind the mentum. Palpi attached 

 to very minute scapes at the anterior angles, pilose, basal joint 

 slender and clavate, 2nd stouter, somewhat obovate, 3rd a little 

 the largest, ovate-conic (5). 

 Head large subglobose : eyes la7-ge lateral and ovate : ocelli 3 in tri- 

 angle on the croivn. Thorax oval : scutel semiorbicular : meta- 

 thorax smooth and convex. Abdomen petiolated, elongated, slender, 

 clavate, basal joint long and slender, the apex nodose and larger than 

 the base of the '2nd joint, the remainder forming an ovate mass. 

 Wings, superior scarcely so long as the body, with a lanceolate mar- 

 ginal cell divided near the apex, one large submarginal and 2 dis- 

 coidal cells. Legs rather short, hinder the longest and stoutest: 

 anterior thighs very short : tibi^ short simple and spurred, posterior 

 stout clavate and spinose externally : tarsi 5-jointed, basal joint the 

 longest and stoutest especially in the hinder pair : claws and pulvilli 

 short and stout (S, afore leg) . 



TiBiALE Fab. — Curt. Guide, Gen. 684. 1. — varicornis Panz. 

 In the Cabinets of Mr. Dale, Mr. Shuckard, and the Author. 



That the neuration of the winn-s is often a valuable and useful 

 character to assist in the formation of genera cannot be denied, 

 but it is equally true that a strict adherence to it without an 



