120 GENERA OF 11 YMEXOl'TERA. 



The peculiar neurution of this? beautiful genus will readily (lir^tin- 

 guish it from all otlu is in the Division. Of the three species that 

 have been described as occurring in our fauna, ahdomimilis and rufi- 

 nodus a})pear to be connnon where they occur :ind arc handsome 

 insects ; the former has the alxlomen entirely red, the first segment 

 not nodose at apex, while in the latter species the first segment only is 

 red, distinctly nodose at apex and the remaining segments ornamented 

 with white ; himaculatus appears to be exceedingly rare, and has not 

 yet been seen by the writer. 



Family PEMPHREDONID.E. 

 Table of Genera. 



Anterior wings without a third discoidal cell and therefore only one recurrent 

 nervure; stigma unusually large. 

 Abdomen subsessile ; recurrent nervure joining the first transverse cubital 



nervure Spilonioiia Shuck. 



Al)domen jietiolate: recurrent nervure received in middle of first submarginal 



cell XligiiHiH Jur. 



Anterior wings with three complete discoidal cells and therefore w itli two recur- 

 rent nervures. 

 Abdomen distinctly petiolate ; head and thorax more or less hairy. 



First submarginal cell receiving both recurrent nervures, sometimes the 



second recurrent nervure is almost interstitial CoiiiOiiiiM .Tur. 



First and second submarginal cells each receiving a recurrent ncr\ ure. 



IViiipliredoii Latr. 

 Abdomen subsessile or with very short petiole: head and thorax not liaii-y; 

 first and second submarginal cells each receiving a recurrent nervure. 



Posterior tibite unarmed; labrum pointed at tij) l*»SNaIw<*ii!i« Shuck. 



Posterior til)ia3 spinose or subserrate; labrum ciiiarginate at tip. 



l>io<l4»iilii!« Curtis. 

 This family is composed of slender, shining black species, mostly 

 small in size, the anterior wings with two submarginal cells, the first 

 being two or three times longer than the second, which is riM'iangular. 

 iSpilomena and Stigmux are remarkable tor the iiniisiially large 

 stio-ma and the absence of the third di.scoidal cell ; the niaiLiiiial cell 

 is much narrowed to the apex, which is acutely pointed; tiie ahilo- 

 men has a long slender petiole in St if/mioi nnd subsessile in Sj/i/onieiui. 

 The s])ecies are quite small, and only three have been described. 



Cemonns and Pemphredon are very closely allied to each other, and 

 have been united by some authors. They differ chielly in the iieiira- 

 tion of the anterior wings as indicated in the above table. The al)- 

 domen has a long, flattened petiole. Only one species in each genus 

 has been described. 



