Manchester Memoirs, Vol. xliii. (1899), No. 11. 17 



and with a basal cell of the characteristic rudely diamond- 

 shaped form, the limbs of which are straighter, indicating 

 by these various characters their affinity to the Old World 

 species. One species of these mimicking forms I will note, 

 namely, Eureleon Hewitson, which is a good mimic, in 

 its typical form and variety, of the heteromorphic species 

 Vertumnus Cram. 



Thus, to recapitulate, we have evidence of the basal 

 cell structure of four groups of genera in two zoological 

 regions, and the structure of this basal cell shows that two 

 groups, one in each region, closely allied, respectively 

 mimic two other offensive groups, one in each region, and 

 also closely allied, thus : 



Old World. 



Bootes mimics Philoxeniis. ^ 

 allied.^ }- allied. 



i^ Eureleon mimics Vertumnus. j 



New World. 

 Having given some idea of the value of the basal cell 

 for classificatory purposes, a few illustrations of the 

 various forms in certain families of butterflies will not be 

 out of place. 



In the family PapilionidcB, to a few genera of which 

 some reference has just been made, the basal cell is con- 

 stantly present, though its general form varies from a 

 large, well-developed form with all its limbs well defined, 

 a type of which is found in the African P. zabnoxis Hew., 

 to a type with more elongated form, such as we get in 

 Vertumnus Cram. It is found in every genus of the 

 ThaidincE which I have as yet examined ; although 

 in Schatz's figures it is not delineated as occurring in 

 Doritis or Ismene. 



In every species of another sub-family, the Parnas- 



