146 The Ohio Journal of Science [Vol. XIX, No. 2, 



vultur 

 fsericea 

 \aktis 



janus 



ferox 



{ gilva 



{ vivax 



fventralis 

 \coquillettii 



tmx 



aimatis 



sadales 

 felis 



Scorpio 



index 

 ithypyga 



{ sicula 



\ franciscana 



{ canis 



{ winnemana 



saffrana 



So far as specialization of the hypopygium goes, an extreme 

 degree in certain directions is exemplified by vultur, by ferox, 

 gilva, Scorpio and ca?tis. Yet these species are not related to 

 each other and cannot be placed together at the apex of an 

 evolutionary series. Evolution is a matter of radiation, and 

 in a linear series this fact forces a wave conception, proceeding 

 from a low degree of specialization along a certain line to its 

 culmination, dropping to the low point of a different line, and 

 so on. 



In the foregoing arrangement sadales and felis occupy the 

 high point with reference to length of third antennal joint, it 

 being nearly three times length of basal joint; in all the other 

 species it is almost exactly twice that length. This is a char- 

 acter possessed by some species of Lampria, and if Lampria 

 were incorporated into the genus Laphria this would be its 

 position — among species which agree in every essential except in 

 possession of spinose hind femora. 



