On the Origin of Bacteria and their Allies. 381 
longitudinal nervures and cross-nervures just beyond the 
opaque part of the tezmina and to beyond the middle below 
the costal area rufo-testaceous, the rest of the cross-nervures 
white. Wings broad, as long as the tegmina, hyaline, and 
with white nervures, except that the longitudinal nervures and 
the branches of the subcostal nervure are pale brown. 
flab. Mbuyuni, Brit. East Africa (Betton). 
This insect agrees fairly well with [schnoptera macra, Stal, 
but is twice the size; from Derocalymma versicolor, Burm., 
it differs in the colour of the legs &c. Both these species 
may, perhaps, belong to the present genus. The female 
probably resembles Perispheria equa, Walk., or Dero-— 
calymma Brunneriana, Costa; but there is no reason to 
identify the male here described with either of these species. 
P4NESTHIINA, 
Genus PANESTHIA, Serv. 
Panesthia nigricans, n. n. 
|| Panesthia nigrita, Sauss. Rey. Suisse Zool. iii. p. 317. n. 17 (1895). 
Hab. Macassar. 
Not Blatta nigrita, Stoll, Spect. Blatt. pl. iid. fig. 6. 
XXXVIII.—On the Origin of Bacteria and their Allies by 
Heterogenesis*, By H. Cuaruton Bastian, M.A., M.D., 
F.R.S. 
[Plates XXV. & XXVI.] 
Ir we turn to the question of the origin of Bacteria and 
their allies by heterogenesis we shall find, I think, that the 
evidence is overwhelming in regard to its reality, though it 
lacks that kind of certitude which obtains in regard to the 
heterogenetic origin of some much larger organisms whose 
birth trom strange ancestors we have been following in some 
of the preceding sections. We may, for instance, as I have 
shown, see the whole substance of a large Rotifer’s egg 
segment into a number of smaller parts, and we may see such 
segments presently become active as Amcebee, Monads, Pera- 
nemata, or even as Ciliated Infusoria f. 
* This paper forms one of the concluding sections of the author’s 
‘ Studies in Heterogenesis.’ 
+ See ‘Studies in Heterogenesis,’ pp. 31 & 46, 
