358 W. HOVANITZ 



An enumeration of the genera (including "groups") of these two 

 types for each family shows : 



Many genera of the northern distributional pattern have close 

 relatives, or even continuity of species, in Eurasia, or, if they do not 

 at present, did in the immediate past when the northern latitudes 

 were warmer. Except when particular circumstantial evidence pro- 

 vides a measure of plausibility, there seems to be no sound basis for 

 inferring that any given form of this type originated in the Old 

 World or the New. 



It can be seen from the figures above that no family has more 

 genera of northern distributional pattern than of panequatorial 

 pattern. If numbers alone were important, this would seem to 

 indicate that all families were, or could be, tropical in origin. Only 

 three families completely lack genera classed as of the northern type. 



Except for the Morphidae, containing the one well-known Neo- 

 tropical genus Morpho, all the families contain genera that do not 

 appear referable to either the panequatorial or the northern cate- 

 gory. In four families, more than half the genera are regarded as of 

 other types. The Papilionidae, however, have but 2 such genera out 

 of 19 genera or groups (Figs. 2-3). These are Euryades and Baronia 

 (Fig. 3), both of which are clearly relict types of restricted distribu- 

 tion. 



The Pieridae (Figs. 3-5) have 7 such types out of a total of 30 

 genera. One of these, Eucheira, is similar to Baronia in range, for it 

 is restricted to a narrow elevated range near the Tropic of Cancer 

 Tatochila complements Pieris in the southern hemisphere and 

 probably should be considered at most a subgenus. Two of these 



