310 Records of the Indian Museum. [VOL sav: 
apparently somewhat fewer than is usual in Cardax willeyi: in all 
other respects the legs resemble those of th'at species. 
Comparative discussion of the venation found in CARDAX 
WILLEYI and in ALILUAUDELLA CAVERNICOLA 
and A, HIMALAYENSIS. 
The diagram given above (text-fig., p. 308) of the tegmen of 
Cardax willeyi illustrates the conclusions thus arrived at with regard 
to the fundamental plan of the venation of that species and will 
form a useful starting-point in the present discussion. 
On comparing this diagram with Shelford’s figs. of Alluaudella 
cavernicola and with fig. 5A of the present paper representing 
A. himalayensis, it will be seen that the ‘* triramose posterior ulna”’ 
of the tegmen of former is the result of the fusion of veins d and e 
with vein EK (a conclusion which is perhaps further supported by 
the abrupt junction of the anterior of the apparent branches 
with the main trunk); whilst the biramose character of this vein in 
A. himalayensis is similarly due to the complete fusion of the proxi- 
mal end of vein e with it. Further, it will be noticed that vein C 
differs from all the other primary veins in having a different point 
of origin in the tegmina and wings, arising from vein B in the 
former and vein D in the latter. ‘Thus it behaves in the two alar 
organs taken together as the secondary veins behave within the 
limits of either of these organs in a single species ; from which it 
may be supposed that its ultimate derivation has been from some 
vein distinct (as the secondary veins now usually are) from the 
system radiating from the origin of the organ. From this the 
following homologies for the different primary veins follow quite 
simply ; A= mediastinal, B=radial, C= vena spuria, D—an- 
terior ulnar, EH = posterior ulnar, F = anal. 
With regard to the origin of the secondary veins there is little 
definite evidence. It may he pointed out, however, that between 
the two branches of a forked primary vein traces of a rudimentary 
vein (see figs. 1 2and 3, x) may sometimes be seen. This vein extends 
from the margin about half way between the two branches of the 
primary vein’ The secondary veins may perhaps have arisen in 
this way, and becoming functional as strengthening organs have 
been fixed by the action of natural selection; though why the 
usual strengthening veins, arising as branches of the primary 
veins, should have been replaced in this way it is difficult to see. 
It will be noted that in this discussion I have assumed that these 
simple cockroaches are degenerate rather than primative. I do this 
because the highly specialized asymmetrical genitalia (see figs. 2 & 
3), and the absence of paired maxiilule, are indications of deriva- 
tion froma normal Blattid rather than immediately from some more 
Thysanure-like ancestor ; and because the junction of the vena spuria 
sometimes with the radial and sometimes with the anterior ulna 
indicates that this vein was originally free proximally precisely as 
it is in other cockroaches. It will be interesting to see, when the 
