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VII. On the terminal ventral segments of the ahdomen in 

 Prosopis, and other Anthophila. By Edward 

 Saunders, F.L.S. 



[Read March 1st, 1882.] 



Plate VI. 



Many authors have described and figured the genital 

 armature of the males in Bomhus and other genera of 

 Aculeate Hymenoptera, but I cannot find that much 

 attention has been paid to the hidden ventral valves of 

 the two segments that immediately precede it, i. e., of 

 the 7th and 8th ; indeed, very few authors have men- 

 tioned the 8th segment in the imago at all, although 

 this segment is very clearly present in all the species I 

 have examined, and in many its ventral valve affords 

 excellent specific characters. 



Leon Dufour (' Eecherches Anatomiques.' &c.) cer- 

 tainly noticed the ventral valve of this segment in the 

 genera Apathus, Bomhus, &c., but he considered it as a 

 part of the genital armature, calling it the " hypotome," 

 and saying that it is inserted or perhaps articulated to 

 a common plate, fixed at the base of the armature below. 



I think there is no doubt that he was wrong in think- 

 ing that this plate is in any way united with the arma- 

 ture, for I have specimens which clearly show its 

 connection with a membrane, which unites it to a mem- 

 branous or sometimes corneous plate, which projects 

 beyond the apex of the 7th dorsal segment, when the 

 abdomen is much extended, and which, I think, is 

 evidently its dorsal valve. 



In extracting the genitalia from dried specimens, the 

 membrane uniting the ventral and dorsal plates of the 

 8th segment, and often also of the 7th, generally gets 

 torn aM^ay, and the ventral plates come away with the 

 armature, so that they have quite the appearance of 

 being part of the actual armature itself. They are, how- 

 ever, easily detached, and the shining smooth under 

 surface of the armature shows no sign of having had any 

 attachment. 



TRANS. ENT. SOC. 1882. PART I. (^APRIL.) 



