130 Annals Entomological Society of America [Vol. XI, 



Table of Sclerites and Appendages. 



somites appendages 



Tipula abdominal is 7, 8, 9, .10, 11 I, II, III, IV. 



Female t+ t+ t+ t+ t— +? — — + 



s+ s-|- s+ s+ s— 



Male t+ t+ t+ t+ t— + + + + 



s+ s+ s+ s+ s — 

 Tahanus sulcifrons 



Female t+ t+ t+ t+ t— _ _ _ _ 



s+ s+ s+ .s+ s — 



Male t+ t+ t+ t+ t— + + + + 



s+ s+ s+ s+ s — 

 CaUiphora viridescens 



Female t+ t+ t+ t+ t— _ _ _ _ 



s+ s+ s+ s+ s — 



Male t+ t+ t+ t+ t— +* + + + 



s+ s+ s+ s+ s — 



j. Hymenoptera. — The connections of the Sth and 9th 

 somites with their respective genitaha are very clearly seen, 

 not only in the generalized saw-fly, Dolerus, but also in the 

 specialized Vespa (Plate XVII). The genitalia, here having the 

 form of saws and stings respectively, are in themselves very 

 naturally greatly modified for their functions, but, except for 

 their length and serrated edges, for example, there is very little 

 about the posterior ends of the females of either of the above 

 mentioned genera which indicates very great specialization. 

 The one point which does strongly suggest such specialization 

 is the complete retraction of parts in this region of the body so 

 that without potash preparations one would see only a perfectly 

 even contour in the caudal region of the abdomen. 



The males of this order show numerous small modifications 

 of all the genitalia, Appendages I, II, III, and IV respectively. 

 These modifications are in the form of many irregular points, 

 curved projections, finger-like evaginations, and other small 

 structures hard to describe. The copulatory habits of these 

 forms have been worked on so little that nothing can be said 

 with regard to the meaning of all these structures. Their 

 positions in relation to their respective segments are not difficult 

 to make out, as is evident from the plates showing figures of 

 these forms. 



