1018 The American Naturalist. [November, 
ENTOMOLOGY? 
The Androchonia of Lepidoptera.—In general all the scales 
of Lepidoptera are modified hairs and originate as papille-like pro- 
tuberances on the surface of the wing. In structure they are at first 
double walled closed sacs, but soon flatten out and strie appear; in 
greatest numbers on the outer surface. The arrangement on the wing 
may be regular or irregular. The coloring is a matter of some inter- 
est and may be due to the refraction of light on the finely ruled surface, 
or a pigment located between the two walls of the sac and away from 
direct contact with the air. But it is not the object of this paper to 
discuss the ordinary scales of Lepidoptera. 
More than 50 years ago Bernan Deschamps observed other scales on 
the butterflies and from their shape called them plumules. The name 
was not a good one however, and has since fallen into disuse. The name 
androchonia was substituted and it is now the one by which the 
so-called scent-scales or hairs of the male Lepidoptera are known. 
The androchonia are found in the same way as the ordinary scales, 
from papillz which rise on the surface of the wing. As regards their 
occurrence they may be massed together in patches or scattered irregu- 
larly over the surface. If in groups they are always concealed by the 
large imbricated scales that seem to be congregated at that point to pro- 
tect them. Often, however, they are protected by being located in a 
pocket or fuld of some portion of the wing, as for example, in one tribe 
the Hesperidi, they are located underneath the reflexed margin of the 
fore-wings. This is their location in Eudamus tityrus where the mar- 
ginal vein is folded back until it no longer forms the outermost edge of 
the wing. 
In the common milk-weed butterfly (Danais archippus) they are 
located at the dark spot on the second pair of wings near the first ven- 
ule of the median vein. In this case they are protected by a prolifera- 
tion of the membrane of the wing which forms for them a pocket. On 
the second pair of wings in Thecla calamus they are simply collected in 
one region on the surface and protected by large scales which are very 
prominent at that point. When scattered irregularly over the wing 
they are always underneath the large scales and therefore well shielded. 
androchonia are very much smaller than the ordinary scales 
and can easily be identified. Some are black or brown but usually they 
are devoid of color. The color given to the patches where they occur’ 
1 Edited by Clarence M. Weed, Durham, N. H. _ 
