24 MELANDER AND BRUES. 



Described from several female specimens collected at Woods 

 Holl, Mass., running about among the burrows of a colony of 

 Halictiis priiinostis Robts. 



This species greatly resembles Mesitius in habitus, but has a 

 transverse furrow at the base of the scutellum instead of two 

 foveje. It can hardly be the undescribed female of E. carbonarius 

 Ashmead, on account of the difference in the sculpture of the 

 metanotum. It is apparently the first subapterous form to be 

 described in this genus. 



Family Formicid.?^;. 



Lasius niger Linneus. 



Stenamma fulvum var. piceum Buckley. 



Solenopsis molesta Say. 



This last named species is the only one that derives any direct 



benefit from the presence of the bees. 



Family Mutillid.e. 

 Mutilla canadensis Blake. 

 This is the most conspicuous of the enemies of the bees. It 

 has been fully noticed in the preceding part. 



Mutilla infensa sp. nov. 



Female. — Clothed with sparse appressed white pubescence becoming 

 denser apically, and with scattered long erect hairs. The hairs are black 

 on the vertex, dorsulum and second abdominal segment and become 

 whitish on the under side of the body and beyond the second segment of 

 the abdomen. Coarsely sculptured species ; head finely and closely punc- 

 tate, thorax and petiole of the abdomen coarsely reticulate, abdomen much 

 less deeply and more distantly punctured than the head, the apical segments 

 with finer punctures, meso and metapleurae shining, not or but little stri- 

 gose, nearly smooth, pygidium longitudinally closely but irregularly striated, 

 the striae very weak and vanishing apically. Head quadrate, concave 

 behind, in profile also rounded ; eyes prominent, round, subshining, their 

 facets distinct ; mandibles straight, strong, pointed, untoothed ; scape stout, 

 as long as the three basal joints of the flagellum, basal flagellar joints sub- 

 equal. Thorax elongate-oval, nearly as broad as the head, the front mar- 

 gin and angles well defined, posterior surface of the metanotum not sharply 

 declivous, somewhat ilattened and rounded above. Petiole of the abdomen 

 flattened above, constricted from the second segment, one fourth broader 

 than long, its front angles sharp and prominent, its ventral carina weak, 



