iQoS] The Genus Coriziis 145 



veins sparingly spotted with black. Abdomen above, black with three small 

 light spots, one on the fourth segment and two on the fifth, the sixth has the con- 

 ventional black stripe bordered by lighter color. The connexivum is light with 

 a small black spot on each segment. 



Too much confidence should not be placed in this color 

 description. The insect is rare, at least in collections, and mater- 

 ial at hand was not sufficient to determine the limits of its varia- 

 tion. It is however, easily distinguished from all others by its 

 genitalia. Specimens are at hand from Texas, Mexico and 

 Hayti. 



PHYLOGENY. 



Any attempt to trace the lines of dispersal or phylogeny of 

 this genus must be merely tentative until more is known of their 

 life histories, food plants, etc. As far as known at the present 

 time, hyalinus is by far the most widely distributed member 

 of the genus, and from the fact that it is found in the tropics 

 and sub- tropics, completely around the earth, we must concede 

 to it very great antiquity. It probably penetrated into the 

 United States by way of Mexico, and thence spread over the entire 

 southern half of the country. 



Sidae undoubtedly has originated in Central America or the 

 West Indies, and has spread as far north and south as the climate 

 or its food plant will permit. Parvicornis is rather an extreme 

 type that is difficult to account for, though it is probably an 

 oflshoot from sidae, as it seems to be more closely related to it 

 than to any other. 



Crassicornis is circumpolar in its distribution, being found 

 entirely around the earth in the north temperate zone, and even 

 far into the boreal regions of North America and Eurasia. It is 

 probable that it originated in the latter continent and thence 

 found its way to America. The winds and tides would favor 

 a migration in this direction, rather than in the opposite. Viri- 

 dicatus is plainly a mountain ofTshoot from this species. 



Scutatus, indentatus and tuberculatus are three species 

 that in many respects, are closely related, and seem to have sprung 

 from a common type. They are all western, and as far as known, 

 not widely distributed, and occupy the same territory. The 

 remaining four species, namely, lateralis, validus, nigristernum 

 and punctatus, form one lateral branch that seems to have sprung 

 from the hyalinus type. Lateralis is the most widely distributed 

 and occupies, practically, all of the United States. Validus is a 

 mountain form very closely related to lateralis, and is not com- 



