I think I've ID this correctly but I can't seem to find any info about it? I think by the name that Clark found it on a penstemon? Anyone know a source for this kind of info. I know its range but that's it. Have not seen it before. We have quite a few penstemons if thats what it's looking for but in this, not so good, photo its on a Buddleja.

http://bugguide.net/node/view/...
it would seem there are a few others in the genus Penstemonia and I guess their larvae eat the roots?

I can't find an exact match, but I found a pdf on the clearwing moths of California. There's a list on page 7 of which species of Penstemon are host to species of moth.

http://www.cdfa.ca.gov/plant/p...

Yes it was there on page seven. The host plant is Penstemon palmeri of which we've had one for two yearsm now. I will check the base of the stems to see if I can find the exit holes. I never expexted they would be feeding off the roots. Thanks you both. The Occasional Papers PDF was fantastic.

There's a key to California Penstemonia species (and others), the final determination of is on page 45, #3 (use find on this page, search for clarkei) which states:

Abdominal segment 6 dorsally banded yellow to nearly white

You can go backwards from that to #2

Anal tuft without elongate lateral portions