( 201 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.)
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