Genus Thanaos 
Early Stages. —Unknown. 
Alpheus occurs in Nevada, Arizona, and New Mexico. 
There are four other species of the genus found in our fauna. 
Genus THANAOS, Boisduval 
(The Dusky-wings) 
Butterfly. —The antennae have a moderately large club, curved, 
bluntly pointed. The palpi are porrect, the third joint almost 
concealed in the dense hairy vestiture of the second joint. The 
neuration of the wings is represented in the cut. 
The fore wing in the case of the male always has a 
costal fold. The butterflies comprised in this genus 
are all, without exception, dark in color, in a few 
species having bright spots upon the hind wings. 
The genus reaches its largest development in 
North America. The discrimination of the various 
species is somewhat difficult. 
,60.— Egg. —The egg is somewhat like the egg in the 
Neuration of the genus Achalarus , but the micropyle at the upper 
genus Thanaos. enc j e gg j s re i a tively larger and not as deeply 
depressed below the surface. The sides are ornamented, as in 
Achalarus , by raised vertical ridges, between which are numerous 
cross-ridges; in a few cases the vertical ridges are beaded, or marked 
by a series of minute globose prominences, upon the edge. 
Caterpillar. —The caterpillars are cylindrical, tapering from 
the middle forward and backward, marked with lateral and dor¬ 
sal stripes, with the neck less strangulated than in the preceding 
genera. 
Chrysalis. —Not greatly differing in outline from the chrysalis 
of the preceding genera, in most species having the outline of the 
dorsum straight on the abdominal segments, with the thoracic 
segments forming a slight hump or elevation; convex on the ven¬ 
tral side, the cremaster being usually well developed. 
(i) Thanaos brizo, Boisduval and Leconte, Plate XLV, Fig. 
7, $ ; Plate VI, Fig. 38, chrysalis (The Sleepy Dusky-wing). 
Butterfly. —The band of postmedian spots on the fore wing 
is composed of annular dark markings, is regular, crosses the 
wing from the costa to the hind margin, and is reproduced on 
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