Wednesday, June 29, 2011

Xylocrius agassizi

Over Father's Day weekend (last week) we decided to celebrate and go camping at Dinkey Creek (at about 5,000 feet and just east of Shaver Lake in Fresno County, California). The campground had just been open the week before. This is quite late in the year but the heavy rains and snow had required the delay. Not long after setting up the tent we took a short walk down to Dinkey Creek by the famous bridge. It was there on a large granite boulder that I saw this impressive longhorn beetle, Xylocrius agassizi.





With antennae poised, it is a bit over an inch long and the black body is heavily punctate and covered with black hair. If you look close you can see that the 3rd and 4th segments of the antennae are roughly equal in length and are more rounded at the end than the later segments. These are diagnostic characters of the species.




It is sometimes referred to (unofficially) as the gooseberry borer because it feeds on Ribes, although I've never seen it recognized as a pest. It probably takes a couple of years to complete its life cycle and is not all that frequently encountered. This particular individual is hardly tarnished at all and seems to have just recently emerged. It's quite an attractive insect in its bold black simplicity. The habitat shot is from Dinkey Creek where I found the beetle but from two years ago when the water was much lower.



3 comments:

beetlesinthebush said...

Nice. I found only a single specimen of this species during my years in California - I got it somewhere up around Lake Tahoe.

Sam Wells said...

Thanks Ted. This was one of those times of just being in the right spot at the right time.

Sam Wells said...

Thanks Ted. This was one of those times of just being in the right spot at the right time.