220 AMERICAN HYMENOPTERA. 



edge of the propodeum, and its sternum with the posterior 

 sides of the rami of the hind plate of the metasternum. It 

 should be noted here, however, that the plate, which is here 

 considered a part of the metasternum, may really be the 

 nestigial neutral plate of the propodeum. The foramen at 

 this connection is, on the thoracic side, a double one, and 

 consists of a lower triangular and an upper circular opening, 

 the two openings running together to a slight extent. On 

 the abdominal side, however, only the lower triangular part 

 of this foramen is present. This is due to the fact that a 

 short tubular membrane, open to a slight extent below, runs 

 back from the circular opening of the foramen on the propo- 

 deum and ends blindly like a sack, the end covering over 

 and enclosing a small Y-shaped extension of the integument, 

 which arises at the lower margin of the first abdominal ter- 

 gum and extends upward and backward a short distance 

 lying closely against the very lower part of the anterior face 

 of the tergum. This membraneous tube encloses a pair of 

 small levator muscles or tendons, and the Y-shaped extension 

 gives them attachment and leverage for raising the abdo- 

 men. The Y-shaped piece together with the tubular mem- 

 brane and the enclosed muscles make up what is known as 

 the funiculus. 



Segments two to five, inclusive, of both the female and 

 male abdomen are very similar in general form and struc- 

 ture. Each one consists of a tergum and a sternum, the 

 former reaching far down on each side of the segment, where 

 it carries the spiracle and overlaps the edge of the sternum. 

 Each of these terga and sterna is transversely oblong, and 

 is widely overlapped by the one next in front of it. The 

 intersegmental membrane in every case runs from the ante- 

 rior edge of the tergum or sternum and attaches to the mid- 

 dle of the inner face of the one in front of it. The exposed 

 portions of most of the terga and sterna are coarsely punc- 

 tate and bear long hair, the terga being — in Bowbus — densely 

 clothed. The covered portions are mostly without punctures 

 and bear little or no hair. The sides of the first sternum 

 and the adjacent portions of the sides of the first tergum are 



