no. 2173. A REVISION OF THE BEMBICINE WASPS— PARKER. 5 



KEY TO GENERA. 



1. Anterior ocellar cicatrix circular or eliptical in form, sometimes placed inapit 2. 



1. Anterior ocellar cicatrix linear, transverse, straight or curved, in a few species the 



ocellus not completely obliterated 4. 



2, Maxillae exceedingly long, when at rest reaching the posterior coxae; maxillary 



palpi with three segments, labial with one Steniolia. 



2. Maxillae shorter, when at rest folded behind the labrum; maxillary palpi with six 



segments, labial with four 3. 



3. Anterior ocellar cicatrix not placed in a pit; seventh tergite of male with lateral 



spines, eighth sternite ending in a single spine and middle femora with a strong, 

 curved tooth below near the distal end Stictia. 



3. Anterior ocellar cicatrix placed in a pit; seventh tergite of male without lateral 



spines, middle femora without curved tooth below at distal end, eighth sternite 

 ending in three spines, and in many species bearing a fourth discal spine - Stictiella. 



4. Posterior surface of median segment concave, its lateral angles prolonged, com- 



pressed and wedge-like; maxillary palpi with six segments, labial with four; 

 eighth sternite of male ending in three spines Bicyrtes. 



4. Posterior surface of median segment flat or convex, its lateral angles rounded; palpi 



otherwise ; eighth sternite of male ending in a single spine 5. 



5. Mandibles dentate; apical end of radial cell of anterior wing on costal border; 



maxillary palpi with four segments, labial with two Bembix. 



5. Mandibles not dentate ; apical end of radial cell of anterior wing not on costal border ; 

 maxillary palpi with three segments, labial with one Microbembex. 



Genus STENIOLIA Say. 



Steniolia Say, Bost. Journ. Nat. Hist., vol. 1, 1837, p. 367. 



Steniolia Tatton, Bull. U. S. Geol. Surv., vol. 5, 1880, p. 364. 



Steniolia Handlirsch, Sitz. Akad. Wissensch. Wien, Math.-Nat. CI., vol. 98, 



Abth. 1, 1889, p. 504. 

 Steniolia Kohl, Die Gatt. d. Spheg., 1896, p. 435. 



Type. — Bembex longirostra Say (monobasic). 



The wasps belonging to this genus vary in length from eighteen to 

 twenty millimeters. The head when viewed from in front is wider 

 than long, its width being about equal to that of the thorax. The 

 compound eyes are large and strongly arched; their inner borders 

 are approximately parallel and below they reach almost to the base 

 of the mandibles. On the f rons between the antennae there is a short 

 but very evident carina. The ocelli are not developed and their 

 cicatrices are sunk in pits; the posterior pair are circular, the anterior 

 one is elliptical, sometimes approaching the circular form. The 

 occiput is very narrow and the cheeks are but moderately developed. 



The mandible, which ends in a single point, has its outer margin 

 entire and its inner margin provided with a tooth near the apex. 

 The maxillae are unusually long, extending when at rest to the third 

 pair of coxae. The tongue, equal in length to the maxillae, is provided 

 at the base with a pair of long thread-like paraglossae. The maxillary 

 palpus is composed of three segments, the labial of one. The labrum 

 is large, blunt, and but slightly emarginate at the apex. It is swollen 

 at the base and appears somewhat pear-shaped. It shows a flat- 



