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XVI. St/nopsis of the British Heterogyna and Fossorial 

 Hymenoptera. By Edwakd Saunders, F.L.S. 



[Read November 3rd, 1880.] 



(Plates VII. and VIII.) 

 It is now about twent3'-two j^ears since the late Mr. 

 F. Smith published his descriptive Catalogue of the 

 British Fossorial Hymenoptera, &c., and since that time 

 so many new sijecies have been discovered, and so many 

 alterations have been made in the synonymy of the 

 species then known, that I thought the short treatise, 

 which I now offer to the Society, giving the more 

 modern views of the subject, might not be unacceptable. 



In it I have endeavoured to give brief and concise 

 descriptions of each genus and species, accompanied by 

 synoptical tables showing their differential characters in 

 a few sentences. 



It is, however, often very difficult to find words which 

 will express the distinctive characters tersely enough for 

 the purposes of such tables, and I hope that, in any 

 cases where the tabulated characters may appear in- 

 sufficient, the actual descriptions will be consulted, where 

 the differences are pointed out more fully. 



The book which has been of more assistance to me 

 than any other in preparing this Synopsis is Thomson's 

 ' Hymenoptera Scandinavige ; ' the aptitude of its author 

 for discovering small structural characters, most of which 

 are really important, although often difficult to lind, is 

 truly wonderful, and I have to thank him for many of the 

 characters here employed. 



I have omitted a good many species given by F. Smith, 

 which appear to me to have little or no claim to a place 

 in our fauna. Some of these he has himself left out in 

 his Catalogue, published by this Society in 1871. 



Altogether I have described 30 species of Heterogyna 

 and 121 species of Fossores. F. Smith, in his last 

 Catalogue, gives 35 species of Heterogyna and 119 

 of Fossores ; but then he places Mutilla, Myrmosa, 

 and Methoca in the Heterogyna, which I have placed in 

 the Fossores. His reason for doing this I have never 

 been able to understand, as the Mutillidse appear to me 

 to have neither the structure nor the habits of the 



TRANS. ENT. SOC. 1880. — PART IV. (DEC.) 



