18.
There is a species approaching the European L. Agestis, and which I received from the head-waters of the San Joaquin River; but the specimens in my possession are too imperfect to allow of an accurate description being given.
19. L. Amyntula, Boisd.
From the Contra Costa hills, where, in May and June, it frequents the flowers of the Pavia, on which the caterpillar probably feeds, as does that of L. Piasus.
20. L. exilis, Boisd.
This species is rare, and so small that it might easily be overlooked. It frequents low meadows and salt marshes, where it loves to repose on the succulent stems of Salicornia, and on the flowers of Frankenia. At present it seems to be the only Californian representative of L. Telicanus and Boeticus of Europe; but I think that several species of this type will be found in Southern California, when that part of the State has been better examined. I have a specimen of L. exilis, collected by Baron de Terloo, in the Sierra Madre, between Mazatlan and Durango; and I received, from the same gentleman, several species of the same type from that locality.
It is this type which is so numerously represented in the tropical regions of the old world, and also in extra-tropical Australia. Our depauperated species, L. exilis, with its two European congeners, are, so far as I know, the only ones of this type which are found in the northern hemisphere beyond the tropics.
All the other Californian species belong to types of the temperate zone, and are such as are rarely met with in tropical countries, or in the southern hemisphere even out of the tropics. The type of Amyntula is the only one which has a series of species in tropical Asia; but, as far as I know, none in tropical America. The type of Piasus, also, has some representatives in the tropics of both continents, one of them being even identified with a species of Southern Europe.
As to the other types, these species are essentially endemic; and even among the Arctic species there seems not to be any amphigeic one. As the males vary very little, and the females only on their upper side, there is little difficulty in transcribing and recognizing them. If among our species there is any one which is identical with an Atlantic one, it is probably Argyrotoxus, which may be a local modification of L. Scudderi, Edw.
Mr. Stearns read the following paper: