1895.] NATURAL SCIENCES OF PHILADELPHIA. 351 



SYNOPSIS OF THE BEMBICINI OF BOREAL AMERICA. 

 BY WILLIAM J. FOX. 



The genera composing this Tribe may be separated as follows: — 



Anterior ocellus linear, transversely arcuate. 



Maxillary palpi six-jointed, labial palpi four-jointed. Middle seg- 

 ment excavated posteriorly, compressed laterally ; last ventral seg- 

 ment ( $ ) with three spines ; mandibles dentate 



Bembidula Burm. 



Maxillary palpi four-jointed, labial palpi two-jointed ; metathorax 

 flat or convex behind, not compressed laterally ; last ventral seg- 

 ment ( $ ) with a single spine; mandibles dentate . Bembex Fabr. 



Maxillary palpi, three-jointed, labial palpi one-jointed ; metathorax 

 and last ventral segment ( $ ) as in Bembex ; mandibles not den- 

 tate MlCROBEMBEX Patt. 



Anterior ocellus elliptic, round or reniform. 

 Maxillary palpi six-jointed, labial palpi four-jointed; anterior ocel- 

 lus round or reniform ; maxillae short Monedula Latr. 



Maxillary palpi three-jointed, labial palpi one-jointed ; anterior 

 ocellus longitudinally elliptic; maxilhe long, reaching the hind 



coxae Steniolia Say. 



In the above table I have considered Microbembex as a genus, 

 notwithstanding my former views. In the respective three-and one- 

 jointed palpi it differs from Bembex about as much as that genus 

 does from Monedula. 



BEMBIDULA Burm. 



Bembex Olivier (in pt.), Encycl. method., IV, p. 288, 1789. 

 Bembidula Burmeister, Bol.. Acad. Cordova. I, p. 122, 1874. 

 Monedula Cresson (in pt.), Synopsis, p. 116, 1887. 



fema les. 



Posterior coxae unarmed 2 



Posterior coxae strongly dentate beneath (wings smoky) . . jodiens. 



2. Last dorsal abdominal segment without a strongly marked pygidial 



area, the lateral ridge feeble, if present ; wings scarcely smoky 3 



Last dorsal abdominal segment with a strongly marked pygidial 



area' the lateral ridges strong 4 



3. Last dorsal segment of abdomen with the lateral ridge present, 



but weak and short 5 



Last dorsal segment of abdomen without any trace of ridges . . 6 



