ODYNERUS. 333 



comparing numerous specimens. It seems nearly impossible to 



determine single specimens upon simple descriptions. 



The details of form and livery upon which J have endeavored 

 to build the subdivisions of the arrangement of the species, are 

 of a very doubtful profit, because of the difficulty of defining 

 them clearly, so that they must not be absolutely relied upon. 



A. Form rather, stouter, abdomen rather wide in the middle, but 

 yet attenuated before. The fossette of the posterior faee of 

 metathorax rounded, always distinct. (Fossette of meta- 

 thorax sometimes margined superiorly.) 



a. Thorax but slightly adorned with yellow; {sometimes quite black, with a 

 yellow spot under the winy) ; post-sculel quite black or adorned with, two 

 yellow dots. 1 



132. O. Morton ian US Sauss. — Niger ; clypeo antice anguste pro- 

 dncto, subbidentato ; mntanoto rngoso, foveola striata, inarginibus 

 punctatis, obtusis ; abdomine ovato, prirao segmento valde punctato, 

 cupuliformi,basi subtrnncato, sessili, secundo magis tenuiter punctato; 

 puncto mandibulari, frontali, post-oculari, lineola in oculorum sinu, 

 macula subalari, punctis 2 post-scutelli et abdominis, segmentorum 1', 

 2' margine tenuiter, flavis ; 2° segmento utrinoue flavo-punctato et 

 partim llavo-marginato ; genibus et tarsis ferrugineis ; tibiis anticis 

 ilavis. 9 • 



Var. a. Thorace omnino nigro, macula flava subalari. — 6. Secundo abd. 

 segmento baud flavo-marginato. 



Odyn. Nortonianus Sauss. Rev. de Zool. XXII, 1870, 105, 28, ?. 



Total lengtb, 9 mm. ; wings, 7 mm. 



?. Rather small. Olypeus somewhat triangular, rather narrowly 

 produced and subbidentate. Prothorax somewhat angulated. 

 Post-scutel short, forming on its anterior (or superior) part a 

 rounded transverse carina, with a little insensible medial tubercle; 

 its hinder face slightly convex. Metathorax rugose, punctured, 

 quite rounded, its concavity strigose, not margin ate. Head and 

 thorax not very coarsely cribrose. Abdomen cylindrical, ovoid ; 

 the first segment short, truncate, and rounded anteriorly, as 

 cribrose as tin 1 thorax, the 2d slightly constricted at base, more 

 finely punctured, becoming more coarsely punctured on its hinder 

 part. 



Comp. also A. l\yroti, var. 



