NORTH AMERICAN HYMENOPTERA. 215 



The Eastern specimens are all perfectly identical, 6.5 mm. long, while 

 the specimen from New Mexico is 4 mm. long, the thorax with more 

 green than the others, but with the abdomen similarly colored. Other- 

 wise, and in the notch, it is the same. Elampus corruscans of Provan- 

 cher belongs to Notozus. 



Oiiialus semicircularis n. sp. — Green and blue with purple reflections; 

 head and thorax pilose, the smoothed areas not very well defined, with scattered 

 punctures. Second joint of antennae a little green; abdomen strongly pilose on 

 the sides and all over the third segment; margins of third segment bisinuate, and 

 on each side of the large semi-circular notch a little produced ; median lobe of 

 mesothorax strongly punctured posteriorly; 5 teeth in the tarsal claw; 5.5 mm. 

 long. % . 



Colorado, one specimen ; very distinct. 



EliAMPUS Spinola. 

 Brull^ Nat. Hist, des Ins. Hym. iv, 53, 1846. 



Occiput with the punctures sparse, leaving some smooth areas ; pro- 

 thorax smooth, the anterior margin punctured more numerous laterally, 

 the posterior margin with one row of punctures and several larger punc- 

 tures in the middle placed irregularly ; mesothorax polished, the sutures 

 with each an irregular row of punctures lengthwise and the sides above 

 the tegulse with a single regular row ; mesothorax evenly punctured, the 

 postscutellum as viewed laterally even, or nearly even, not forming a 

 horizontal blade as in most species of Notozus. Species, however, may 

 be found that possess this character to a marked degree, as it shows itself 

 to be variable in both genera. 



Dorsum of postscutellum as viewed laterally even, not projecting posteriorly. 

 Entire lateral margins of third abdominal segments arcuated, or with a single 

 broad shallow sinus; the snout-like prolongation of apex very slight, 



abrupt Cressoni. 



Lateral margins of third abdominal segment with two arcuations, or bisinuate, 



the prolongation strong, tapering variatus. 



Dorsum of postscutellum, as viewed laterally, projecting a little posteriorly. 



specnlum. 



Elainpus Cressoni n. sp. — Head and thorax with the smoothed areas 

 dark blue with slight purple reflections, punctured areas with green reflections; 

 abdomen dark blue, purple and green, third segment short, abrupt ; margins with 

 a single arcuation or sinus, the snout-like projection slight, i.e. hardly extending 

 from the ordinary line of the margins, but truncated ; tarsal claws with two teeth ; 

 3-.^>.5 and 4 mm. long. % . 9 



Montana and Colorado, three specimens. 



Elampus variatus n. sp. — In the majority of my specimens the head and 

 thorax have the smoothed areas dark green with blue and slight purple reflec- 



