154 HYMENOPTERA OF AMERICA. [rART I. 



first forming a little rugose crest ; the trench of this last bordered 

 with trenchant and? rugose ridges. Abdomen very slender; the 

 first segment lengthened, funnel-shaped ; its upper face as long 

 as wide, rather coarsely punctured, divided by an indistinct 

 groove; the suture strong, arcuate. The other segments smooth. 



Insect black. A spot at the summit of clypeus, another 

 between the antennae, a dot behind each eye, two spots on the 

 prothorax, one below the wing, two on the scutellum, and the 

 border of segments 1, 2, 4, yellow. Tarsi ferruginous beneath ; 

 tibiae marked with yellow at the summit; the anterior pair yel- 

 low. Wings transparent, a little washed with brown. Wing 

 scales black. 



Var. a. Spot on the clypeus very small, 



b. Clypeus wholly black. 



%. A little smaller. Clypeus, rounded and bjdentate, pale 

 yellow; mandibles yellow before, bordered with black; a yellow- 

 line on the scape of the antennae ; extremity of the flagellum a 

 little ferruginous beneath. The yellow dots of the head and 

 thorax small; that under the wing sometimes wanting. A yel- 

 low border upon the 5th segment. Tibiae yellow; tarsi yellow, 

 gray at the extremity. Groove of the first segment deeper. 



Hess. a. cliff. — This species greatly resembles the 0. sinuatus 

 Fabr., although its markings are less rich. But its first abdoini- 

 minal segment is much less coarsely punctured and the dividing 

 groove much less pronounced. It differs from the 0. pumilus in 

 its much greater size, in its first segment being less rugose, aud 

 in. its different ornamentation. 



Hab. Xorth America. Pennsylvania. Xew York. Canada. 

 Prairies. Fort Tejon. California. 6 9,1$. 



3. S. alljosnarsiiiaiiis Sac?s. — Niger, punctatus ; metanoto rugoso; 

 abdominis primo segmentn grosse punctata, sutura elevata; puncto inter 

 antennas et frequenter altero in satnmo clypeo, macnlis 2 pronoti, 2 

 scutelli, pnneto subalari abdominisque segraentoram 1-4 raarginibas j 

 albidis; til'iis albido-variis ; tarsis subtus ferrngineis. Alis hyalinis. 

 Lougit, 9 nun. 



Variat. Abdominis tertio segmento baud marginato. 



Odi/iients albomarginatus Sauss. Et. Vespides, III, 1854, 195, 90, 9 . 



Hab. America boreal is, Hudson's Bay. (Typus in Mus. Lon- 

 dinensi.) Connecticut. (Ed. Norton.) 



