118 



xcrces has no black centers and being the oldest description applicable 

 to this species (1852 1. c. p. 296) must hold the specific. name. It is 

 unfortunate that the next two descriptions referable to this species 

 should be of rather abnormal forms; antiacis Bdv. (1852, p. 300) is 

 a large form with rather broader borders on the upper side than usual 

 and with a slightly different arrangement of black centered spots on 

 the underside of secondaries, spot 2 of the postmedian row being absent 

 and spot 1 closely approached to the costal spot above the discocel- 

 lular; it is figured by Oberthur (1. c. Fig. 1951) ; we have no specimen 

 just like it, but have a specimen of typical xerces showing this pecu- 

 liarity. Wright erroneously figures the Southern Calif, race of behri 

 under this name; his mertila is also not typical but an intergrade 

 between polyphemus and xerces. Mertila Edw. (1866) is close to the 

 normal black spotted form but between the discocellular lunule and 

 the base of wing on primaries is a white dash ; this form occurs in both 

 sexes and in both the spotted and unspotted forms. Polyphemus Bdv. 

 (1869) is the first name applicable to the normal spotted form; there 

 are many intergrades between this and xerces and also towards mertila 

 and in one 5 before us which we figure the spots on one side are 

 typical xerces and on the other side just as typical polyphemus, a fur- 

 ther proof, if needed, that but one species is under consideration ; there 

 is also occasionally considerable reduction in the spots, such specimens 

 passing under the name of orcus Edw. but as already stated we con- 

 sider orcus referable rather to pheres than to xerces. 

 The synonymy of the species would be : 



xerces Bdv. 



form ah. antiacis Bdv. 

 form ab. mertila Edw. 

 form norm, polyphemus Bdv. 



The food plant of the species is given by Williams (Ent. News, 

 XIX, 478) as Lotus glaber and the larva is stated to be separable from 

 that of behri Edw. The species seems to bear the same relation to 

 behri that pheres does to icarioidcs, being a species peculiar to the 

 sand dunes of the Pacific coast. 



G. behri Edw. 



After careful study of the original description we agree with 

 Williams in adopting this name for the species closely allied to xerces 

 found flying around the San Francisco Bay region (vide. Ent. News, 



