1927] Study of the Male Abdominal Appendages of Apantesis 139 
free edge of the inner layer is sharply defined. The lower border 
of the clasp is excavated near its middle, proximal to which it 
curves inward. This inward curve becomes more marked in 
prepared specimens, and as it is impossible to flatten the clasp 
without distorting it, the drawings show this part of the lower 
edge upturned. 
The uncus consists of a broad basal part which joints the 
tegumen, and distally becomes spear-shaped as seen from above, 
beak-like laterally. There is a deep groove where the broad 
base of the uncus joins the tegumen, which is hardly noticeable 
from above. The ventral half of the tegumen shows no charac- 
teristic differences in the group, except that it is narrower and 
more pointed in radians and phalerata. The juxta in the news- 
group as seen from below appears cone-shaped, and projects 
from the manica. In other species of the genus it consists of a 
thickening of the manica which remains closely apprest to the 
sedoeagus. 
The organs are so curved, especially the claspers that great 
care is necessary in making comparisons, for a slight difference in 
orientation will make a great difference in the apparent shape °f 
the organ. For this reason the usual balsam mounts were found 
unsatisfactory in this study, and after preparing the genitalia in 
the usual way and studying the structures as a whole the com- 
ponene organs were dissected apart and compared unmounted. 
Before beginning the study of the genitalia the specimens were 
sorted into the different groups on superficial characters. The 
genitalia of seventeen specimens of nais were examined, twenty- 
one of vittata, (besides seventeen of the aberrant brood), eight of 
radians, (including floridana), and fifty of phalerata. All the 
radians were from Florida; the other series included moths from 
various localities. Each series included specimens showing wide 
variations in maculation. 
A. nais (Figs. 1-7). The usual form of the clasper is shown 
in Fig. 2. Variations occur in the relative length and width of 
the part, the length of the rounded apex, and the degree of cur- 
vature of the posterior (distal) edge. Fig. 3 shows a clasper in 
which all these variations appear. In all the species variations 
occur in the size and shape of the costal arm, the extent of the 
