510 Dr. T. A. Chapman on the 
various authorities who ought to have known better have 
confounded them. 
Lasistrigalis is very distinct from any other species. 
There are two other forms that seem to be very probably 
really only forms of one species. ‘These are sudetica and 
petrophila. Petrophila is the smaller and darker, yet it 
can hardly be called either a more northern or more alpine 
form. I take it, however, to be a local race of the more 
wide-spread sudetica, the appendages are identical. 
I add a few notes on the appendages of each species 
that will make the photographs of them more easily 
understood as to the points of specific distinction they 
possess. 
I have to regret that I have not mastered any satis- 
factory way of spreading these appendages for observation. 
They are rather awkward and obstinate, and at the same 
time small and delicate, so that one has to accept a poor 
result rather than persevere at the risk of considerable 
damage to the specimen. 
Centuriella (figs. 2-5) has large dense appendages. The 
aedoeagus is rather narrow, there are no cornuti, the 
uncus is not tapering as in the other species, but has 
nearly parallel sides narrowing only a little to a broad 
blunt tip. The tenth sternite * also thicker before the apex, 
and on its upper surface has some minute rough teeth; 
the large clasps have some not very definite basal thicken- 
ing, they also have a spine about the middle of the 
ventral margin, but this springs from quite a soft margin 
of the clasp, it is short and blunt, and is free from hairs 
only in a short terminal portion. 
The question as to whether ambigualis and atomalis 
(figs. 8, 10, 11, 12, 18) are distinct species seems to be 
fairly settled in the negative without reference to the 
appendages. So far as structure goes these also appear 
to be quite identical. I found one or two typical speci- 
mens of each form differed quite decidedly in size, but 
before undertaking to consider how far this suggested 
distinct species, local races, or what not, I thought it best 
to measure some specimens without reference as to which 
species they might belong, this partly because I could 
* I propose to point out elsewhere that this is usually called the 
scaphium ; it is, however, subanal, but is not the sub-scaphium of 
Pierce. The scaphium of Gosse is supra-anal. Pierce is the only 
authority who seems to have understood this. 
