Sept.,igo6.j CooK: VALIDITY OF THANAOS AUSONIUS. 127 



Fig. 10 represents the genitalia of martialis as seen from below 

 (25 diameters) showing the angle at which the clasps in each instance 

 were mounted for examination. 



It will thus be seen that the modifications observed in the clasps 

 of the individual named Thanaos ausonius are well within the limits 

 of the variation exhibited by the species T. martialis. 



I next removed with a bristle a few androconia from the costal 

 fold of the left wing of "ausonius," and found them identical with 

 the androconia of martialis. 



The only other difference worthy of note is the absence of the hya- 

 line spots. Of martialis, ninety-one females were examined and one 

 hundred and twenty males. The number of such areas on a wing 

 was found to vary from seven to three. The location of the several 

 spots is shown in fig. 13 and for easy reference I have lettered them. 

 Xo single specimen had more than seven of the possible eight, the 

 one + showing a, lacking 9 within the ceil. The most persistent of 

 these spots are s, % and r h all of which appear in each of the speci- 

 mens examined. The ? $, as the more conservative element of the 

 species, constantly show a tendency to retain all ; the rPd 1 as the 

 more variable element tend to lose them. As ausonius is a cf I shall 

 here give only the results of my examination of the males. 



a was missing in 120, 



j3 " " " III. 



W " " " 109, 



) " " " 19, 



(5 " " " 6, 



t, ,*, // were " " o. 



In three specimens £, t and r y , the only ones which persist, are 

 greatly reduced and of rounded outline, and it does not seem to me 

 that the loss of these is sufficient warrant for the specific distinction 

 of a butterfly no second specimen of which has ever been taken. 



These hyaline areas are little patches of the membrane which have 

 been partially denuded of scales, the atrophied insertion of each one 

 of which is plainly visible with a ,V objective. But the denudation 

 is only partial, many of the scales persisting, although for the most 

 part wanting in pigment. Yet not always unpigmented, for occasion- 

 ally a single one or a group is to be found furnished with the rich 

 dark brown color of the submarginal spots in which the hyaline areas 

 are set. 



