1914.J NATURAL SCIENCES OF PHILADELPHIA. 177 



mimetic, and, if Danaida plexippus had never entered America, it is 

 highly improbable that anything more than the corresponding 

 colored markings would have been evolved on the wings of the female 

 terlooti. The range of tints in the markings common to menapia and 

 terlooti gives an indication of the variational material out of which 

 selection built up the mimetic pattern. The peculiar shade of 

 yellow of the under surface of the hind wing, the rich orange of the 

 central parts of the upper surface, the paler tints of the marginal 

 markings, especially at the apex of the fore wing, the emphasis by 

 black pigment of the veins of the hind wing upper surface, are all 

 elements in producing the result — a somewhat rough but at a distance 

 almost certainly a deceptive mimetic likeness to D. plexippus. 



The same considerations help us to understand the prevalence of 

 Pierine mimicry in tropical America as compared with other parts- 

 of the world — because of the predominant Ithomiince and Danainoe 

 with warning patterns made up of reds, yellows, whites, and blacks. 

 Such patterns are mimicked by the Pierine genera Dismorphia 

 (in the broad sense), Perrhyhris {'' Mylothi'is^'), Archonias, Hes- 

 perocharis, and we can now add the, North American Neophasia. 



8. The Restriction of Sex-limited Inheritance to the Mimetic 

 Pattern of Neophasia terlooti. 



The older colored markings common to the females of menapia 

 and terlooti are only partially sex-limited, being inherited in a very 

 reduced form by some of the males of the former species and probably 

 by all of the latter. The more modern mimetic pattern of the 

 female terlooti is strictly sex-limited. The facts harmonize Avith the 

 hypothesis that female mimicry is largely due to the great variability 

 of this sex in Lepidoptera ^nd the freedom with which it offers to 

 selection a wide range of sex-limited colors and markings, but that 

 when a pattern has been long established it tends to be transferred 

 to the opposite sex. 



The older non-mimetic marginal markings suggest that the trans- 

 formation of uric into lepidotic acid is especially easy in this part 

 of the hind Aving and invite comparison with the number of mimetic 

 Neotropical Pierines in which marginal or submarginal reds have 

 been developed in the same position, viz., on the under surface of 

 the hind wing — a study that would carry me too far from the subject 

 of the present paper. 



12 



