PSYCHE 
VOL. XXXIV. JUNE-AUGUST, 1927. Nos. 3-4 
A STUDY OF THE MALE ABDOMINAL APPENDAGES OF 
THE NAIS-GROUP OF APANTESIS WALKER . 
(LEPIDOPTERA ARCTIIDvE) 
By Elmer T. Learned, M. D. 
Fall River, Mass. 
The genus Apantesis is composed of moths well known for 
their variability, a character especially marked in the four forms: 
nais Drury, vittata Fabricius, radians Walker, and phalerata 
Harris. The close relationship of these moths suggested that it 
would be interesting to examine the male abdominal ap- 
pendages in a series, to see to what extent these organs vary, 
and whether constant structural differences exist between the 
forms as separated by superficial characters. Before considering 
the genitalia I propose to summarize briefly what is now known 
about these moths. 
The range of variation in these insects is so wide that it is 
impossible to give a description which will always serve to dis- 
tinguish one form from all its allies. Each tends toward a certain 
characteristic type, however, and in spite of the similarity in 
markings the moths are readily separable into the four forms. 
With a knowledge of the habitus of each form and appreciation 
of the factors which are apt to vary it in one or another direc- 
tion, only old or worn specimens and occasional extreme varia- 
tions should cause confusion. 
Nais includes specimens predominantly yellow in colon, 
comparatively robust thorax with rough vestiture, the collar 
most often immaculate, the pattern of the fore wings usually 
complete or nearly so, always with black costal edge; the hind 
