MR. LUBBOCK ON THE THYSANURA. 
431 
It must, however, be observed that, in a new genus about to be described, the antenna? 
cannot properly be called « elbowed," though they are often held in a bent position. 
The same is the case with the Smynthurus viridis, figured in Cuvier's ' Re<me Animal ' 
. xiii. fig. 3, which, as M. Nicolet suggests, is not a true Smyat hums, but belong 
probably to my new genus. 
The family at present contains only two genera, Smynthurus and Dicyrtoma, 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, Bourlct. 
Antennas eight-jointed, five before, three after the bend. Two dorsal tubercles on the 
abdomen 
Papiritjs, Lbk. 
Antennas 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 Smynthurus and Papirius appear to me to indicate a separation of more 
than generic value ; and we can never hope to obtain just ideas of the affinities 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 Thysanura I can, how- 
ever, only express myself in a provisional manner. 
For the present, I have only to record three English species of Smynthuridas, 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 antennas 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. signatus ; but 
the antennas 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 distinguish 
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 Kicolet, as I shall presently 
point out more fully. 
vol. xxiii. 
3n 
