2 7 6 



THE STUDY OF INSECTS 



twig with silk so that it cannot fall during the winter. So far as is 

 known all of the species of the sovereigns hibernate as larvae in nests of 

 this kind, it is worthy of note that only the autumn brood of cater- 

 pillars make these nests; so that the nest -building instinct appears only 

 in alternate generations, or even less frequently when the species is more 

 than two-brooded. B. archippus is found over nearly the whole of the 

 United States as far west as the Sierra Nevada Mountains, and has been 

 found sparingly even to the Pacific coast near our northern boundaries. 



THE EMPERORS 



This group is poorly represented in our fauna; our best-known species 

 are the two following, which occur in the South. 



Fig. 477. — Chlorippe clylon: a, eggs; b, larva; c, pupa; d, upper 

 surface of male butterfly; the dotted line at left indicates the contour 

 of the wings of the female. (From Riley.) 



The tawny emperor, Chlorippe clyton. — In this species the apex of 

 the front wings and the anal angle of the hind wings are considerably 

 produced in the males, but more rounded in the females. The male is rep- 

 resented in Figure 477 and the dotted line at the left indicates the con- 

 tour of the wings of the female. This excellent figure is from the sixth 

 Missouri report by C. V. Riley, where a detailed account of the life- 

 history of the species is given. The wings of this butterfly are more or 

 less obscure tawny, marked with blackish-brown, and with pale spots. 

 There is a submarginal row of six eye-like spots on the hind wings. 



The species is dimorphic; the dimorphism affects both sexes and is 

 independent, so far as is known, of season, as there is only one brood each 

 year. It is the typical form Chlorippe clyton clyton that is figured here. 

 The second form, Chlorippe clyton proserpina, differs in having the hind 

 wings darker and the submarginal row of eye-like spots wanting. 



The larva (Fig. 477, b) feeds on hackberry. 



THE AN^AS 



The butterflies of the genus Ancea are quite distinct from any of the 

 preceding divisions of the Nymphalina?, although they have been classed 

 with the emperors. There are three species found in the United States, 

 A. portia from Florida, A. morrisonii from Arizona, and the following 

 one. 



