Are there 3 species here or did you mean salicirhodoides instead of salicicoryloides.

I meant what I said.

Was just curious as this post on bugguide is the only internet result for that species!

What leaf shape does salicicoryloides have? I've been faced with several different looking Rabdophaga galls on willows recently but I'm still not sure what species (plural?) I am dealing with.

I see now that I left out an "s", probably because I copied and pasted John's spelling (it's spelled correctly in my book). You may get more hits with "saliciscoryloides". The relevant couplet in Gagne is as follows:

8a Gall leaves open, flared, the gall shorter than wide: R. saliciscoryloides.

8b Gall leaves more sessile, the gall longer than wide: R. salicisrhodoides.

Here is the entirety of Gagne's notes on R. saliciscoryloides: "Galls are 5-7 cm long and 5-10 cm in diameter. The difference between these and galls of R. salicisbrassicoides and R. salicisrhodoides may be only superficial. Host: S. ?discolor. Distr.: Illinois. Ref.: Walsh (1864)."

This gall was nowhere near 5-10 cm and the leaves comprising it were indeed long and narrow (as sandbar willow leaves inherently are anyway), so this must be R. salicibrassicoides. I initially called this a "bud" gall based on its terminal location on the branch, but on second examination the "scales" look very leaf-like. Does R. salicibrassicoides create a distorted bud or just a cluster of leaves?

Galls like this are referred to as bud galls, but are clearly made up of many leaflike structures. I'm guessing that the midge oviposits in a single bud and it happens early enough in the bud's development to somehow produce a proliferation of leaves. The mechanisms of gall formation are a mystery to me.