126 PROCEEDINGS OP THE CALIFORNIA 



plants of the most different families, still clings with such tenacity to a cosmo- 

 politan plant, to whose universal distribution it is perhaps much indebted for 

 the wide range which it itself attains. 



Next to the cosmopolitan character of this plant, P. Cardui owes its great 

 extent probably to its many generations and certain irregularities in the time 

 of the appearance of the perfect insect ; so that small colonies of the species 

 are not so liable to be destroyed by inclemency of climate or exceptional atmos- 

 pheric agencies ; for a being that exists at the same time in the four stages of 

 the egg, larva, chrysalis, and imago, has more chances of escaping cataclysms 

 and deluge than others that are all at one time in the same stage of existence. 

 The extent of the infl lence exerted by the number of generations, and the irreg- 

 ularity of period, can be very clearly recognized by the circumstance that 

 species with one generation are always the most local ; for instance, certain 

 Melitece, Argynnidce, Ineclcc, most of Sphingidce, etc. ; that also the cosmopoli- 

 tanism develops in proportion to the number of generations, and attains its 

 maximum in certain Vanessidce, Danaidce, Pyrameis, etc. 



Pyrameis Hunteri Fab. 

 This species seems to have, in California, but one generation. It is not com- 

 mon. I have found it only in the latter part of the season, and have not yet 

 succeeded in finding the caterpillar. The genus Pyrameis has the widest range 

 of all the genera of this family. It extends through all latitudes from the 

 Arctic regions to the Cape of Good Hope and Cape Horn. On the northern 

 hemispheres it is best represented in California, which country possesses one 

 peculiar species in addition to all three of Europe and the Eastern Slope of the 

 United States. 



Junonia Hubn. 

 Junonia Cccnia Boisd et Lee. 

 Several generations. Caterpillar not yet found in California. From this 

 enumeration of California Vanessidce we find, 1st. That with the exception of 

 V. Californica, there is not yet found any species of this group peculiar to our 

 State, for even P. Carye exists as well in Chili as here, and is also said to have 

 been found in Brazil. This circumstance is more striking since our Argynnidce 

 and Melitece prove altogether local ; none of them being identical with East- 

 ern species, unless a Melitcea, of the type of Mylitta, should be found identi- 

 cal with a form found in Texas. 2. The genera of this group, north of the 

 Tropic of Cancer, are essentially amphigeic, the European Arachnia being 

 almost the sole exception. But, as it were, to compensate this, the tropical 

 amphigeic genus Junonia, wanting in Europe, extends, on our continent, to high 

 latitudes. 3. As regards the number of specks, the genus Grapta predominates 

 at the Eastern Slope, Vanessa in Europe, Pyrameis in California, and our own 

 Junonia is counterbalanced in Europe by our Arachnia. 



