ACADEMY OF NATURAL SCIENCES. 125 



whether it has its vernal generations somewhere else in adjacent countries. I 

 have found but one colony of caterpillars. It was in July, and most of the 

 individuals were nearly full grown ; they were rather delicate, the majority died 

 in the larva state, seven transformed about the end of the month, and a single 

 chrysalis produced a crippled butterfly. 



Vanessa Milbertu Godt. 

 This species is common in woody localities. The caterpillar is very much 

 like that of V. Californica, and only a few individuals show a distinguishing 

 mark in the shape of a longitudinal, lateral stripe of sulphur yellow. It feeds 

 on Urtica. 



Vanessa Antiopa L. 

 There is nothing to add in regard to this long and well-known species. The 

 caterpillar feeds here, as everywhere else, on willows. 



The true Vanessa? have about the same geographical distribution as the Grap- 

 tae. They also have a predilection for Urticaceous plants. Only the most 

 northern species is amphigeic. 



Europe. California. Atlantic Slope. 



V. Antiopa. V. Antiopa. V. Antiopa. 



V. Urtica. V. Milberti. V. Milberti. 



V. Polychloros. V. Californica. V. C-album. 



There is a balance in favor of the Old World — the beautiful type of V. Io 



not being represented on this continent — and also the type of V. Polychloros, 



containing a few species, as, for instance, V. Xanthomelas, that make it appear 



more numerous. 



Pyrameis Hubn. 

 Pyrameis Atalanta L. 



Larva feeds on Urtica. 

 Pyrameis Carye. 



This species is by far the most common butterfly in California. The cater- 

 pillar is very variable in its coloration, and is so like that of P. Atalanta, in 

 company with which it is frequently found, that I have never succeeded in find- 

 ing any distinguishing characters. It feeds throughout the year on Urtica and 

 on several malvaceous plants, and has the habit of all its congeners, of hiding 

 itself in a rolled up leaf. 



Pyrameis Cardui L. 

 This most cosmopolitan of all diurnals, affects here, in its larva state, several 

 malvaceous plants, and also the genus Gnaphalium, and its relations ; but the 

 plant for which it shows the greatest predilection is Silybum Marianum, a 

 plant which formerly did not exist here, and has only spread since 1852. It now 

 forms thickets in the neighborhood of San Francisco, as well as near most of 

 our inland towns, but has never spread to a great distance from settlements. 

 P. Cardui frequents the same localities, and I found the same species in Aus- 

 tralia in the same relation to the same immigrated plant, Silybum Marianum. 

 I know very well that P. Cardui existed here, as well as in Australia, before 

 the immigration of this Mediterranean plant ; but still, it is a remarkable fact 

 that this cosmopolitan butterfly, notwithstanding its ability to adapt itself to 



