1865.] 223 



terior wings in Citheronia sepulc rails, nobis, is produced in different 

 colors in its congener. Both species have the veins marked with 

 brighter scales and the anterior pair of wings spotted at base. 



Among other material kindly sent by Mr. Treat for examination, 

 new to science and which will be illustrated by Mr. G-rote in a future 

 paper, is the individual of this species from which we have prepared 

 the foregoing description. The specimen is in excellent condition and 

 has been reared from the larva, which latter, judging from Mr. Treat's 

 observations, is nearly allied to that of Citheronia regalia, its more 

 brilliant but hardly more beautiful congener. Assiduous collecting in 

 the locality as well as in other allied districts, will doubtless be rewarded 

 by the discovery of further specimens of this fine species which adds 

 greatly to the beauty of our lepiclopterous fauna. The appreciating 

 hand of the careful Entomologist is shown in the uniformly good con- 

 dition of Mr. Treat's specimens and is worthy of general imitation, 

 when we reflect that perhaps the greatest value of material belonging 

 to the present Order consists in its perfect preservation. 



With alcoholic preparations of the £ imagos of Anisota stigma, pel- 

 lucida and rubicunda before us, we do not appreciate sufficient distinc- 

 tive structural characters to warrant a separation of the latter from the 

 other species of the genus Anisota. The pterogostic characters are iden- 

 tical in all these species, while the shape of the anterior wings under- 

 goes a slight modification, since in A. stigma and pellucida they are 

 broader and more triangular, owing to the greater length of the exter- 

 nal margin and consequent depression of the external angle, while the 

 apex is more produced than in A. rubicunda ; the shape of the wing 

 is somewhat inconstant however in this genus and is different in sexes 

 of the same species. The antennal structure is identical in all three 

 species while the pectinated basal joints seem hardly so exaggerated in 

 A. rubicunda. We fail to notice structural differences in the head and 

 mouth parts or in the thoracic region, and although when we consider 

 the coloration of A. rubicunda it seems foreign to Anisota, we see little 

 divergence from the pattern of ornamentation which is a character of 

 greater value. x\n analagous case of striking divergence of color be- 

 tween a single species of a genus and the majority of its congeners may 

 be cited in the instance of the European Saturnia coeclgena. From 

 all that we can learn, the larva of A. rubicunda is similar to those of 

 the other species of the genus, while we notice that in this group the 

 generic position of the imago is well indicated in the modifications of 

 larval structure. 



