Taken at night, late April. Sonoma Co. Weather: nice- night temps low 50s. Apologies for the less than great photo. Pair appeared to possibly be mating. Size was about 1/2"-3/4" (excluding long antennae). Bellies were a chartreuse greenish-yellow, long antennae, distinct markings along back. I have not seen crickets like this before. Couldn't find anything similar in google searching. Photo was taken hurriedly with a mobile phone camera so poor quality. Another photo of poorer quality captured the bright color on the stomach better. I have heard a very muted thrumming sound, like a minute knocking and wondered what it is; heard it that night but don't know if these were the bugs making the noise.