82 Journal New York Entomological Society. [Voi. v. 



The thorax is very convex, there are two high prominent tubercles 

 on the scutellum, which are higher and longer than in Andrena, also 

 two smaller ones on the meta-scutellum (none on the port-scutellum). 

 The propodeum is more like an abdominal segment than a thoracic one ; 

 it is broad and square-cornered, twice as broad as long, not yet sepa- 

 rated from the abdomen. The latter is now one-half larger than the 

 head and thorax. The segments posteriorly are very convex, and the 

 edges very distinctly, thickly and finely dentate ; the end or terminal 

 segment of the abdomen is long and slender. 



The presence of the four deciduous semi-pupal tubercles on the head, 

 which in this stage are so large and distinct, and which are arranged in 

 a transverse line just in front of the ocelli, is interesting and deserves 

 further investigation, as their use is unknown. The fact that all these 

 tubercles disappear afterwards is of additional interest, also the circum- 

 stance that they do not exist at all in the corresponding stages of Apis 

 and of Bombiis is perhaps a characteristic of that sub-family of Apidae 

 i^Andreneice) of which Halictus is a member. 



The pair of tubercles on the meso-scutellum and meta-scutellum are 

 also of corresponding interest. They are scarcely homologous in po- 

 sition with those of Oxybelus, except those on the meta-scutellum. The 

 serrate, very convex abdominal segments are noteworthy, as being a 

 " low" feature. Also noticeable are the great differences between the 

 two high posterior tubercles on the sides of which are situated the two 

 posterior ocelli, so different from the anterior sunken ocellus. 



Andrena vicina Smith. 



Larva. — In Andrena vicina the larva is not only much larger, stouter 

 and thicker than that of Halictus (^H.parallelus and ligatus), and not so 

 long in proportion, but the thickened tuberculous portion of the segments 

 is broader, and not so sharply ridged. The two tubercles on the head 

 are more prominent. The clypeus is wider and squarer, and the entire 

 clypeal region broader ; the mandibles are stouter and blunter, as are the 

 maxillae ; the best characters are the stouter, more truncate mandibles, 

 and the more raised tubercles on the vertex. 



Head with the vertex rather deeply impressed by the median line; 

 on each side is a high, prominent, acute tubercle. The lateral region on 

 each side of the depressed median portion bulging, convex. This median 

 region is divided into two slightly convex pieces. The clypeus is divided 

 into an anterior and a posterior portion. The labrum is nearly square, 

 quite distinct from the clypeus ; the edge is square, the sides narrowing 

 very slightly towards the front edge. On each side of the front edge of 



