1927 ] Study of the Male Abdominal Appendages of Apantesis 141 
nais is seen by comparing Fig. 2. A more definite angle at the 
junction of the posterior and upper margins in vittata is the only 
difference, (the shape of the costal arm and of the lower border is 
of no importance) and sometimes serves to distinguish them, but 
is not constant. The specimen in Fig. 9 (which happens to be 
from a large moth) has as evenly curved a posterior edge as has 
nais. The other extreme is shown in the clasp with flattened, 
oblique, posterior margin (Fig. 16). The uncus is similar to that 
of nais and varies to the same extent. The basal part tends to 
be less rounded in vittata with the sides more sloping, but Figs. 
5 and 12 were selected to show the different forms, and are not 
intended to imply a constant, specific difference. The usual 
form of the juxta is shown in Fig. 10. It varies in length and 
in three specimens was as long as in nais, (Fig. 11). 
The aedoeagus is similar to nais, but thruout the series a 
constant difference was found in the callum. It differs from 
nais in the proximal end, which flattens out and blends into the 
normal chitin, while in nais this end becomes twisted. There is 
more variation in vittata in the shape of the spine, several varia- 
tions of which are shown (Figs. 8, 14, 15); one specimen was 
found with a long, bifurcated spine. Fig. 15 shows the closest 
approach to nais found in the series, in the short, broad callum 
(the shape of the spine is not important) but the proximal end 
shows the difference noted. 
Figs. 17-21 are from specimens of the aberrant brood of 
vittata mentioned above. The s&me peculiarities were found in 
two generations. The claspers are not distinctive. Tho rela- 
tively long and narrow, with an unusually broad arm, they are 
probably within the range of variation of vittata. The uncus is 
remarkably different, having the spear point nearly twice as 
long as in any other form, and with prominent rounded 
“shoulders” on the basal part. It was the same in all the 
specimens examined. The juxta has a broad, blunt end. The 
aedoeagus differs from the normal vittata in the absence of the 
lateral bend of the distal portion of the callum, and has two 
diverging, nearly equal spines. Two specimens were exceptional 
in having but one spine, thus resembling normal vittata. The 
occurrence of a double or bifurcate spine as an aberration 
