In one of my first posts, I wrote about some goldenrod rosette galls I collected and the things that were emerging from them. I pointed out how this female torymid wasp could be recognized by her long ovipositor, which allows her to insert eggs deep within galls.
Well, I just came across some photos I took in July that show a torymid–which may or may not be the same kind–that I found on a goldenrod rosette gall, putting her ovipositor to use.
In the next photo, you can see the actual drilling apparatus (stylets), angled forward, while the protective sheaths hang straight down from the end of the abdomen.
There are two stylets and two sheaths, even though each pair of valves looks like a single unit in the photo. The presence of two sheaths is better seen in the following series, in which a giant ichneumon (Megarhyssa atrata) drills her outrageously long ovipositor deep within an old sugar maple to lay eggs in the tunnel of a wood-boring pigeon horntail (Siricidae: Tremex columba) larva.
Megarhyssa atrata, incidentally, is the largest known parasitoid wasp in the world, with the longest ovipositor of any arthropod. The ovipositor can be up to 142 mm long, or more than 5½ inches. The adult female of its host, the pigeon horntail, has a comparatively tiny ovipositor, although it is large compared with those of most other insects. It is likewise used to bore into wood. The one below has its stylets, visible as a black line, poking straight down into the wood, while the red sheaths remain in their normal position.