254 Mr. F. Smith on new Genera and 



so exceedingly close a resemblance that no decided specific di- 

 stinction has yet been satisfactorily pointed out, however probable 

 it may be that such distinction may exist. 



Why, therefore, the one should be popularly styled a " wild 

 Horse," and the other a " wild Ass," it is difficult to comprehend. 

 Even Pallas terms the Dshiggetai " un Cheval sauvage," though 

 describing it as " ni Cheval ni Ane f while the other he both 

 designates as the Ass of the steppes and as the " Cheval ou Ane," 

 employing the word " cheval " in its German equivalent evidently 

 in the sense of equus. Col. Chesney, as we have seen, terms the 

 Arabian A. hemippus a " wild Horse," as distinguished from his 

 wild Ass of South Arabia ! The fact is, I apprehend, that the 

 vague application of these names has resulted merely from the 

 colouring. 



XXXII. — Descriptions of new Genera and Species of Tenthredi- 

 nidse in the Collection of the British Museum. By Frederick 

 Smith. 



The collection of Tenthredinidse contained in the national 

 Museum is perhaps the most extensive in Europe ; the species 

 described in the present paper are, in my own opinion, the most 

 remarkable in the various genera to which they belong. The 

 Hylotoma imperialis is unrivalled both in size and beauty by any 

 of the species of that extensive genus. The new Lyda is the 

 first species which I have seen from the East, and is remarkable 

 for the extreme elongation of the antenna?. The new genus 

 Derecyrta is, however, the finest addition to the family. The 

 new species of Sir ex must acquire additional interest from the 

 fact of its being discovered in the cedars of Lebanon. Having 

 been engaged in the preparation of a Catalogue of the Tenthre- 

 dinidse for some time past, and it being obvious that its com- 

 pletion will occupy still a considerable length of time, I have 

 thought it desirable to secure to myself the description of a few 

 of the more remarkable species and genera of this family of 

 insects. 



Genus Hylotoma, Latr. 



Hylotoma imperialis. 



H. nitens, supra purpureo-violacea ; capite, thorace abdomineque infra 

 nigro-chalybeis ; alis flavo-hyalinis ; antennis nigris, opacis. 



Female. Length 8 lines. Brilliant purple, with violet tints 

 above, varying in different lights ; beneath of a steel blue, very 

 smooth and shining ; the antennae of an opake black ; the wings 

 yellow hyaline, the nervures reddish-yellow. 



Hob. North China. Robert Fortune Esq. 



