THE CANADIAN ENTOMOLOGIST. 425 



THE RHOPALOCERA OF SANTA CLARA COUNTY, 



CALIFORNIA. 



BY KARL R. COOLIDGE, PALO ALTO, CALIF. 



Santa Clara County borders on the Bay of San Francisco, extending 

 back therefrom through the Santa Clara Valley to the Santa Cruz 

 Mountains, which perhaps average 2,500 ft. in altitude. Owing to the 

 diversity of the topography, many species are found to be very locally 

 confined. For instance, Gceides gorgon is but rarely met with in the 

 valley, its habitat being on the hot, dry hillsides where Eriogonum thrives, 

 The home of the Argyimids is on the highest ridges, and they are seldom 

 seen elsewhere. To the bay region no species are strictly confined, but 

 some of the Lyc<^nidce and Hesperidce are more abundant there than else- 

 where. Along the inner sloughs, where Salix occurs, a few species, such 

 as Papilio rutulus and eurymedon, Basilarchia Lo?-quinii and Limenitis 

 Bredowii, var. caH/ornica, which have willow or oak for their food-plant, 

 are common. In the valley proper a great majority of the species occur. 

 There is a sharp distinction in the faunal aspects, although only a few 

 hundred feet difference in altitude between the valley and the foothills. 

 In the hills, Mifuulus and Castileja furnish food for the Lemoniids, which 

 fly in countless numbers. Many species of Lyccenidce have for their food- 

 plants Luphius, ^sculus and Hosackia, which occur everywhere in the 

 hills. To the mountain region a number of species, such as Chrysobia 

 7?iormo, Hahrodias grtmus and others, are confined. Thus, one might 

 collect here for years and then not have taken all the species. This 

 localization can be accounted for directly by the range of the food-plants. 

 In the open fields of the valley, Euchloe sara and auso?iides are common, 

 flying about Brassica, their food-plant. Ascending into the hills, 

 ausotiides becomes rarer and higher up is never met with. Sara, on the 

 other hand, flies -almost everywhere, but I am quite positive that in the 

 hills it has a different food-plant, as mustard is "few and far between," and 

 sara is often found fa*r away from it. I might say here that I do not 

 believe in determining species by the localities from which they come. It 

 should be remembered that butterflies, like other insects, must be allowed 

 some variation which the effects of climate, etc., impose upon them. In 

 some of our genera, particularly Argyjmis and Levionias, which have 

 many western species, a large number of these so-called species will prove 

 but geographical forms of others. Lepidoplerists distinguish between 

 Lemo?iias Wrighiii and iea?iira because one is from Southern California 

 and the other from farther north. If a $ JVrig/itii {(wm Los Angeles) 

 and a ^ leanira (from San Francisco) should meet, I am sure they would 



November, 1908 



