Assassin bug with green legs and red abdomen

2015 March 11

On July 16, 2014, Rosie presented me with this rather spindly, delicate-looking true bug. It was about a centimeter long (half an inch).

Unfortunately, she kind of mangled it in the process, with the wings all disarranged and tangled up with the long hind legs. She didn’t kill it, though.

Although, disarranging the wings did clearly expose the red upper side of the abdomen, which we probably wouldn’t have seen otherwise.

It was only the top side of the abdomen that was red, the underside was more of a pale greenish-orange.

The general body shape, with the long head, distinct neck, and stout piercing-sucking mouthparts all suggest that it is an assassin bug. And the size and body configuration looks most consistent with the genus Zelus. I’d originally thought maybe it was the Milkweed Assassin Bug, Zelus longipes, based on the red abdomen, but Rosie’s specimen isn’t anywhere near orange enough (plus, it looks like a southern species that wouldn’t be up here anyway). It may be Zelus luridus, which is normally pale green [1] but looks to have significant color variation (and does definitely live this far north).

So anyway, as an assassin bug this would be a predator on all sorts of soft-bodied creatures, particularly aphids and caterpillars. And if it really is in the genus Zelus, then it has the unusual feature of secreting sticky material on its legs, and using its sticky legs to capture prey (kind of similar to how a Sundew catches insects). Unfortunately, I can’t tell from the pictures whether its legs are sticky or not, although the way that it couldn’t seem to untangle its legs from its wings suggests pretty strongly that they are.

[1] When I saw “luridus”in the species name, I thought it meant that it was brightly colored, which is pretty much what “lurid” means in English. But this would be an odd name for something that is normally pale green. It turns out that in the original Latin, though, “lurid” means “pale”! So, in the course of stealing the word from Latin[2], we also apparently completely inverted its meaning.I kind of wonder just how that even happened.

[2] “We don’t just borrow words; on occasion, English has pursued other languages down alleyways to beat them unconscious and rifle their pockets for new vocabulary.” – James Nicoll

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