I rescued this fascinating-looking bug from the pool yesterday afternoon. I think it must belong in the Geocoridae, but it looks nothing like the other specimens I have found around my place. My guess would be that it is one of the Isthmocoris species -- though not particularly similar-looking to the I. piceus images on this site, I did see some similarities with this image of I. imperialis. On further researching the possible Isthmocoris species, I was very intrigued by the possibility of I. tristis, for which I could find no images to compare... Van Duzee's Catalogue of the Hemiptera references it as being found in CA, and McAtee's Key to the Nearctic Genera & Species of Geocorinae gives the following brief, but compelling description:

"Geocoris tristis is probably a synonym of one or the other of the above species. ... Judging from the known rage of piceus and imperialis, the latter is most likely prove a synonym of tristis. ... The name tristis would certainly be a misnomer for this most gaily colored of our species of Geocoris."

It is that last bit of text that perks my interest, as the red coloration of this specimen seems quite striking. Very eager to hear the opinions and input of others!

Surrounding habitat is chaparral and mixed oak woodland.