192 PROCEEDINGS OF THE ACADEMY OF [Jan., 



common to other individuals of each species examined by Eltringham 

 and, as regards three of them, by Burgess. 



Knowing my own want of experience in the comparative study 

 of these male abdominal appendages, I submitted Dr. Eltringham's 

 drawings to my friend Dr. Jordan, who wrote, Aug. 15, 1913 : "Archip- 

 pus appears to be a later modification of obsoleta. as you say. Astyanax 

 ■arizonensis, weidemeyeri, and arthemis are also closely related to one 

 another."* Dr. Eltringham also agrees that the comparative study 

 of the armatures supports the conclusions arrived at from a study 

 of the patterns. 



Considering together pattern and the structure of the claspers, 

 there are strong reasons for believing that the mimetic forms arose 

 from a North American Limenitis with the pattern of arthemis and 

 weidemeyeri, but including a white spot in the fore-wing cell upper 

 •side now seen most commonly in lorquini among North American 

 species, and with claspers like those of weidemeyeri and arthemis, 

 l)ut probably nearer to the former. 



I trust that Dr. Skinner will consider that this evolutionary 

 bistory, if not convincing before, has been rendered so by the fresh 

 evidence now produced. 



12. Similar Environmental Conditions versus Mimicry as an 

 Interpretation of Color Resemblances. 



With regard to the resemblance of Limenitis {Basilarckia) flori- 

 densis to Danaida herenice in Florida and of L. (B.) obsoleta (hidsti) 

 to D. strigosa in Arizona, Skinner suggests (33, p. 127) that "similar 

 .environmental conditions explain these color resemblances better 



^ The remainder of Dr. Karl Jordan's letter contained an interesting and 

 suggestive criticism of Scvidder's conclusion that ]>roserpina is a hybrid between 

 ■arlhemis and astyanax. 



"The differences in the genitalia between astyanax and arlhemis might render 

 copulation a little difhcult, but' are too insignificant to prevent it. According 

 to ^cudder, proserpina is the hybrid between astyanax and arthemis. If that is 

 the case, the genitalia should be intermediate. As they are identical (teste 

 Hcudder) with those of the northern insect, I do not believe that proserpina is a 

 Jiybrid. The offspring of a 9 proserpina were partly proserpina, partly arlhemis. 

 This also points in the direction that astyanax has no part in the production of 

 proserpina. Scudder appears to rely particularly on this point — proserpina 

 inclines towards astyanax where the latter prevails, and towards arthemis in the 

 places where this insect is abundant. But such an agreement in coloration may 

 .sim])ly be due to the two occurring side l)y side. It is not necessarily evidence 

 for hybridization. I have only looked at Scudder's book, not at tlu; specimens; 

 my opinion is therefore worth very little, but I incline to the belief that arthemis 

 .assumes the pattern of astyanax where it com(>s into contact with the latter, i.e., 

 that proserpina is a southern modification of arlhenris, not a hybrid. It would 

 be advisable, however, to examine the genitalia of a series of specimens of all 

 three insects." 



