no. 2374. NEW WASPS OF SUBFAMILY NYSSONINAE—ROHWER. 411 



Type locality. — Bair's Ranch, Redwood Creek, Humboldt County, 

 California. 



Type.— Cat. No. 23459, U.S.N.M. 



Described from one male collected June 12 by H. S. Barber, for 

 whom the species is named. 



NYSSON (BRACHYSTEGUS) OPULENTUS, var. DAKOTENSIS, new variety. 



Male. — Length, 7.5 mm. Differs from the typical form in having 

 the markings more distinctly yellow, in the apical band on the first 

 two tergites being complete and in having a transverse yellow spot 

 on the first tergite before the apical band. The punctures on the 

 first two tergites are also a trifle larger. 



Type locality. — New England, North Dakota. 



Type.— Cat. No. 23457, U.S.N.M. 



Described from a single male collected by C. N. Ainslie. 



Tribe HOPLISINI. 



The definition of this tribe is changed from that given in the 

 Connecticut Hymenoptera only by the omission of the phrase, "mese- 

 pisternum without an oblique suture from below tegula to prepectal 

 carina." This change permits the inclusion of the genus Arpactus 

 Jurine and certain species of Hoplisoides which would otherwise be 

 excluded. 



At least in some cases the convergence of the eyes toward the 

 clypeus is a secondary sexual character. 



Key to the North American Genera. 



1. Nervellus straight, antifurcal; mesepisternum with an oblique suture from below 



tegula to the prepectal carina Arpactus Jurine (=Dienoplus Fox). 



Nervellus long and strongly curved, interstitial or postf ureal. Hoplisus Lepeletier. 



Genus HOPLISUS Lepeletier. 



Of the three subgeneric groups tabulated below it seems probable 

 that more material will make it difficult to satisfactorily separate 

 Hoplisus in the restricted sense and Hoplisoides, but the smooth 

 propodeum makes it easy to recognize species belonging to Pseudo- 

 plisus. 



Key to North American subgenera of Hoplisus. 



1. Propodeum smooth and shining, practically without sculpture; propodial inclosure 



well defined; nervellus distinctly postfurcal Pseudoplisus Ashmead. 



Propodeum sculptured, the inclosure usually striate 2. 



2. Propodeal inclosure well defined; nervellus postfurcal Hoplisus Lepeletier. 



Propodeal inclosure not or scarcely defined; nervellus interstitial, 



Hoplisoides Gribodo. 



