Fossorial Hymen optera of North America. 405 



Mimesa Cressonii n. sp. 



$ . Head much as usual, striated behind the ocelli, which are farther 

 apart than usual, situated in a low equilateral triangle; eyes smaller 

 above, and farther apart than in M. argenti/rons ; surface of the vertex 

 densely, but minutely punctured, polished, not hairy; front widening 

 equally above aud below, not so broad as in M. argenti/rons; clypeus 

 narrower and more convex on the front edge, surface more convex than 

 in the preceding species, tubercle between the antennae much as usual; 

 below the ocelli the front is somewhat bronzen yellowish silvery, with 

 much fine pubescence just in front of the ocelli; mandibles black; 

 antennae very clavate, brown above, and pale reddish on the sides and 

 beneath, scape black, basal joint of flagellum black at base beneath. 

 Prothorax much higher and larger than in M. argenti/rons, with a 

 delicate, but dense line of pubescence just behind the crest, surface of 

 thorax minutely punctured, polished ; meta-scutellum hirsute. 



Propodeum with triangular enclosure striated, striae proceeding un- 

 interrupted to the posterior part of the propodeum, where they are fine 

 and regular, parallel, diverging from the mesial furrow; posteriorly the 

 pubescence is long and hirsute, silvery -yellow; with no distinct mesial 

 furrow as in M. argenti/rons. Fore legs dark fuscous, two posterior 

 pairs black; two fore femora slightly reddish at tip, and tibiae reddish 

 at tip aud base; tarsi reddish; hind tarsi dark brown, paler towards 

 tip of joints, wings clear iridescent; tegulaa testaceous, nervures dark 

 brown, costa ferruginous. Abdomen with the pedicel a little longer 

 and slenderer than in 31. appressifrons, 2d ring entirely red ; 5th red 

 at base, rest of tip black ; terminal segment dull colored, very densely 

 punctured, tip with a very slightly marked broad flattened area, with 

 a short pubescence, area not, however, so well marked as in M. apprts- 

 si/rons. 



Length, .35 — .45; head and thorax, .18; abdomen, .27 inch. 



New Jersey, (Coll. Ent. Soc. Phil.) : New York, (Norton). 



As indicated on the label, by Mr. Cresson. this fine species is un- 

 described, and I take pleasure in naming it after him. By its large 

 size, bronzen front, finely striated propodeum, its antennas with the 

 under side red; and by the entirely red three (2d — 5th), basal rings 

 of the abdomen, and the very slightly flattened tip. it will be readily 

 recognized. M. appressi/rons differs in the rather coarse net-work of 

 fossulets on the propodeum, in the mesial furrow, and having the base 

 of the 2d abdominal ring black, while the front of the head is much 

 narrower. 



