NORTH-AMERICAN HETEROCERES STRECKER. 273 



Dimidiata, Stretch, are doubtless but the yellow, red and black varieties 

 of one and the same species. Callimorpha Dominula, L., occurs with 

 yellow and black hind wings, as well as crimson. (J. Hera, L., is found 

 with both red and yellow secondaries. Arctia Persephone, Grote, has a 

 variety, with inky black abdomen and secondaries. This has. been de- 

 scribed as a separate species by Grote under the name of A. Anna. 

 Arctia Figuraia, Dru., occurs with black as well as scarlet inferiors. A 

 Achaia, G.-R., Virgo, L., Parthenice, Kby., Nais, Dru., and Phyllira. 

 Dru., all are found in both the yellow and red winged forms. 



In fact, with the exception of A. Yarrowii. and a few others, that are 

 as yet only knovvn by the types, or one or two other examples, A. Vir- 

 guncula, Kby., is. I believe, the only species of all those known to me in 

 nature in which I have seen no variation from the normal yellow type, 

 unless the insect lately described by myself as A. Oithona be a red-winged 

 variety of it. None, however, present a greater number or more astound- 

 ing variations than the common A. Caja, L., found in both the old and 

 new world. Those found in North America were considered a distinct 

 species and described as such by Dr. Harris, under the name of A. Amer- 

 icana, on account of having the front of the collar edged with white. 

 This distinction, however, failed in validity when examples were also 

 found in Europe having likewise the white collar. Ordinarily this spe- 

 cies has white primaries, with broad brown diverse shaped marks, which 

 latter cover the greater part of the surface, and orange colored seconda- 

 ries, decorated with many large black and steel colored spots, these spots 

 varying considerably in number and size in diiferent individuals; but 

 examples occur in which the brown marks of primaries are reduced to 

 very inconsiderable spots or streaks, completely altering the whole ap- 

 pearance of the insect. Another and more startling aberration is one in 

 which the primaries are entirely uniform brown, and the secondaries en- 

 tirely black ; both of these monstrosities are figured in Humphrey's 

 British Motlis. Other examples occur with the secondaries yellow, and 

 finally Dr. Staudinger discovered in Syria, in 187."), a local form, in wliich 

 the secondaries of the male were pure white, and those of the female 

 very pale orange ; the brown marks on the primaries were very insignifi- 

 cant ; this variety was described by Dr. S. as Caja var. Wiskotti. 



Thus I might go on almost endlessly emimerating varieties without 

 number, but enougii have been alluded to to give some idea of the extra- 

 ordinary freaks, be they climatic or otherwise, to which these insects are 

 subject. That the aberration of. Caja, figured by Humphrey, with 

 wholly brown primaries and black secondaries, is a suffused example, in 

 which the dark color of the markings predominated to the total exclusion 

 of the pale ground, is easily to he inferred, though not to be explained ; 

 but why some examples should have yellow hind wings, and others found 

 only in a certain locality, should have them white in one sex and orange 

 in the other, is a matter as yet to me totally inexplicable. 



