Atalopedes campestris campestris
Sachem or Field Skipper
This uncommon skipper is at least double-brooded, and may be found as early as March and as late as October if you happen upon it. Males have a large stigma that sets it apart from other grass skippers. I happened upon them along grassy roadsides around Valyermo, north of the San Gabriels, in September of 2008. Ken Davenport has written (Emmel update) that they are "extremely abundant" at Weldon in late September/early October.
Emmel, Emmel, and Mattoon (Systematics, pp.22-23) reckoned that Pierre Lorquin likely collected the type specimens "in the bottomlands near the Sacramento River". These were sent to France for Boisduval, who named Hesperia campestris on the basis of a male. He didn't realize he had a female as well. See below and the sylvanoides page.