Greatly resembles A. pistillariiformis but I won’t be so bold as to assign a species name to an Amazonian Cordyceps anamorph with only this photo and without microscopy.

EDIT: If it is indeed A. pistillariiformis that would make this the anamorph of Cordyceps tuberculata. (http://www.fruit.affrc.go.jp/...tuberc.htm)

insect host was a moth, about 3 cm long.

What part is insect and what part is fungus?? (And if someone has time, what is an “anamorph”? And why does it get special distinct generic status?)

how big was the insect host?

I believe this is an Akanthomyces species. They are Cordyceps anamorphs, and there are a couple of species that occur on Lepidoptera (adults and larvae). They tend to be pale and a bit lovely.

This is the anamorph of a Cordyceps, formally assigned to the genus Isaria. (Perhaps Isaria sinclairii ?)
Fantastic picture!
Karl

Cool fungus. Cordyceps species are soooo weird. Thanks for posting

Very strange and nice to see! We have nothing like this in California.