210 Dr. T. A. Chapman’s 
worked out, but with so much collaboration and assistance 
from Mr. Elwes, that he is quite able to accept the con- 
clusions from my work as readily as if he had arrived at 
them without my assistance; as doubtless, in fact, he 
would have done had I not relieved him of the necessity 
of following this line of research more exhaustively. I 
have to acknowledge the assistance received from him in 
various ways and from various other friends for specimens 
and material; of these I may mention Messrs. Nicholson, 
Tutt, Jones, &e. 
I do not propose to discuss the homologies of the organs 
forming the male genital armature in Hrebia. They con- 
sist of the following portions:—An upper portion, the 
tegumen (tegmen 2) or sicula (uncus and scaphium ?), with 
a central and two lateral processes; two lateral portions, 
the clasps or valves (combined valve and harpes?); a 
ring of chitin continuous with the tegmen and supporting 
the clasps ; the penis; two chitinous ridges between the 
ring and the penis on either side. 
In £rebia as in most other Lepidoptera, it is the clasps 
(or valves) that present the most distinctive characters in 
different species, so that in nearly all cases the species 
may be at once named from its clasp; and this being so, 
one naturally pays less attention to the other appendages, 
which with a closer study might probably be found to be 
equally characteristic. 
The tegumen or sicula (why not anglicise this as‘ sickle’ ?) 
varies comparatively little as regards the central or upper 
process, which usually has a somewhat regular curve, and 
a nearly equal diameter throughout; its chief variation 
is in length and the sharpness or bluntness of the tip. 
Here dried specimens are apt to be deceptive, from twist- 
ing and curling, especially if previously treated too freely 
with alkaline preparative. The lateral arms are more 
variable, they almost always have a slight curve and 
taper to a point, but they may be longer or shorter, more 
or less sharp, and so forth. In a few instances they are 
distinctive ; thus in LZ. xthiops (Group ITI), viewed laterally, 
they are seen to be expanded at the end and to terminate 
obliquely at nearly their full width instead of in a point. 
In £. radians they are of nearly equal width throughout, 
sweep round in an S-curve and terminate in a rounded 
end. In #. disa, EF. embla and £. cyclopius, they expand 
at the extremity into a racket-shaped disc, a form to 
