HENRY J. FRANKLIN. 219 



form, anterior plate, located between the mesocoxse, and a 

 separate triangular, posterior scale-like piece which extends 

 from this anterior sclerite back between the hind coxae and 

 reaches the edge of the median segment by means of two 

 rami or arms. These arms bound the abdominal foramen 

 (the opening into the second abdominal segment) below. 



Propodeum. — This large single sclerite, as has been abund- 

 antly proved, is really the notal plate of the first abdominal 

 segment, which has become thrown forward and joined solidly 

 to the thorax, the corresponding ventral plate having become 

 lost. It fits into the hollowed out posterior edges of the 

 metathorax. Its surface is convex and it bears the first ab- 

 dominal spiracles laterally. These spiracles are elongate 

 and curved from end to end. The surface is finely punctate 

 in the middle and densely and coarsely punctate on the sides. 

 It is divided into an upper median area and two lower 

 lateral areas by two delicate, slanting and sinuous grooves 

 which meet on the middle line near the lower margin. It 

 bears only short pubescence on the middle portion, but there 

 is usually considerable pile on the sides. 



Abdomen. — Without the propodeum, the abdomen of the 

 females (queen and worker) has six exposed segments 

 fig. 1) and that of the male seven. With the male, how- 

 ever, only the tergum of the seventh segment is exposed, 

 its sternum being the outer spatha of the genitalia. For 

 convenience, the propodeum has not been considered in the 

 numbering of the segments in the detailed descriptions of the 

 various species ; they have there been numbered from front 

 to rear as though what is really the second segment were 

 the first one. Counted in this way, the tergum of the first 

 segment is the largest abdominal sclerite. It has a large 

 triangular, anterior face and it runs down onto the venter on 

 each side and overlaps to some extent the comparatively 

 small ventral plate or sternum. Its anterior face is usually 

 either concaved or furrowed longitudinally in the middle ; 

 this face has only very fine punctures for the most part and 

 does not bear much pile. In the attachment of this segment 

 with the thoracic box, its tergum connects with the lower 



TRANS. AM. ENT. SOC. , XXXVIII. 



