nictitans group of the Genus Hydroecia. 745 
We turned next to the genitalia. As will be readily seen 
by the plates which accompany this paper, these organs 
in the four species—and in H. americana, Spr. (atlantica, 
Smith), the common North American species belonging to 
the same group—are closely related in general configura- 
tion, although the details are different. It is these differ- 
ences that 1 would now point out. 
First considering the males. 
Taking our commonest species, MH. nictitans, we find 
that the claspers (valves) are tipped with a more or less 
rounded head (cucullus). There are no external free 
angles; there are spines along the outer margin for about 
half its length (corona), and a bunch of spines upon the 
rounded, not pointed, anal angle. The “harpe” is boot- 
shaped, the stout inner and outer branches being of equal 
length. The clavus is claw-shaped, curved towards the 
centre, and is clothed with hair. The “vesica” is armed 
with a bunch of long thin “cornuti.” These vary in 
number between about four and eight; and also in length, 
but I have never observed any of these in this, or the 
other species, within the “ bursa copulatrix” of the female. 
In H. paludis there is a marked difference in the form 
of the “cucullus,” which is larger, and distinctly angulated. 
The “corona” extends nearly three-quarters of the dis- 
tance along the margin, the anal angle is obtusely pointed, 
and bears a large bunch of spines. The “‘harpe” is 
boot-shaped, but has a long toe and a short heel. The 
“clavus” is long and pointed at the end. The “cornuti” 
are short and stout, being some nine to twelve in number. 
Hf. lucens has the “cucullus” much narrower than the 
last species. It is angulated—the “corona” extends 
further along the margin of the “cucullus,’ which is 
sharply pointed on the anal angle, and bears a proportion- 
ately smaller bunch of spines than does paludis. The 
“harpe” is boot-shaped, the toe long, much like the last 
species, but the heel is longer and strongly curved out- 
wardly. The “clavus” is slightly shorter than in paludis, 
and often blunter at the tip, almost obtuse. The “ cornuti” 
are long and fine, and from ten to twelve in number. 
The genitalia of these three species are of similar type, 
but the remaining species which I have examined depart 
markedly from them. 
Hf. crinanensis has the “cucullus” very much narrower 
than either /ucens or paludis, being nearly twice as leng as 
