MR. LUBBOCK ON THE THYSANURA. 431 



It must, however, be observed that, in a new genus about to be described, the antennae 

 cannot properly be called " elbowed," though they are often held in a bent position. 

 The same is the case with the Smyntlmrm viridis, figured in Cuvier's ' Eegne Animal,' 

 pi. xiii. fig. 3, which, as M. Nicolet suggests, is not a true Smtjutlmrus, but belongs 

 probably to my new genus. 



The family at present contains only two genera, Smynthurus and Bicyrtoma, to which, 

 however, I am now about to add a third. 



Smynthurus, Latr. 

 Antennae four-jointed, bent at the insertion of the fourth, which is nearly as long as the 

 other three, and appears to consist of many small segments. No conspicuous 

 dorsal tubercles. 

 Of this genus I have to record a new species. 



DicYRTOMA, Bourlet. • 

 Antennae eight-jointed, five before, three after the bend. Two dorsal tubercles on the 



abdomen. 



Papirius, Lbk. 

 Antennae four-jointed, without a well-marked elbow, and with a short terminal segment 

 offering the appearance of being many -jointed. 

 I have to describe two new species of this genus. 



I may, however, be permitted to remark that this is, to my mind, far from being a 

 natural classification of the group. The great differences in the organs of respiration 

 existing between Smyntliim'us and Fapirius appear to me to indicate a separation of more 

 than generic value ; and we can never hope to obtain just ideas of the afiinities of different 

 groups of insects until more attention is paid to the internal organization. On the 

 principles which ought to guide us in the classification of the Thysanm-a I can, how- 

 ever, only express myself in a provisional manner. 



Eor the present, I have only to record three English species of Smynthuridae, all of 

 which are, I believe, as yet undescribed. Doubtless many others exist in this country ; 

 and I am indeed myself acquainted with two or three, of which, however, I have not 

 yet been able to obtain a sufficient number of specimens. 



Smynthurus Buskii, Lbk. Body globular, with scattered hairs ; abdomen with a re- 

 entering angle. Colour brown, with a light patch in the form of a V on the 

 posterior half of the abdomen. Apical portion of spring and end of the tarsi 

 whitish. Basal part of antennae three-jointed, and about of the same length as 

 the terminal ringed portion. 

 This short description is enough to distinguish it from any of the species hitherto 

 described. In general colour and form of body it approaches nearest to S. slgnatus ; but 

 the antennae of that species are longer, and have the basal part consisting of three small 

 segments between two longer ones — a character which is at once sufficient to distingmsh 

 them. The colour also differs a little. It must, however, be observed that S. signatus 

 of Templeton is quite a different species from S. signatus of Nicolet, as I shall presently 

 point out more fully. 



VOL. XXIII. 3 N 



