When one observes a moth or butterfly chrysalis from which the adult has emerged, is the “evidence of presence” more properly a “construction” or a “molt”? Or maybe “it depends”?
A chrysalis is just a pupa with a fancy exoskeleton. It’s not something that the caterpillar built. So what’s left of a pupa or chrysalis after an adult has emerged is a shed skin, not a construction.
But if there was a cocoon built with silk, shed hairs, etc., that would be a construction.
i annotate it as organism unless it’s empty, in which case molt
The silk pad a chrysalis is hanging from is a construction fwiw, but the empty chrysalis is a molt
I think that whatever a caterpillar constructs should be considered a construction: the silk pad that a butterfly chrysalis is hanging from, the cocoon that many moth chrysalises are inside of, and the cases and bags that some tiny moth larvae (like Psychidae and Coleophoridae) carry around.
The chrysalis itself is essentially a skin, an actual part of the living organism that it can’t live without until it’s ready to crawl out of it. An empty chrysalis is called exuviae, which I suppose can be called a molt in English.
I’m sorry, I can’t help myself…exuviae is plural, one shed exoskeleton is an exuvia
Exuviae is always and only found in the plural 
The Latin word exuviae,[3] meaning “things stripped from a body”, is found only in the plural.[4] Exuvia is a derived singular form, although this is a neologism, and not attested in texts by Roman authors. A few modern works use the singular noun exuvium (e.g.[5]). Only a single historical work by Propertius uses the singular form exuvium, but in the meaning “spoils, booty”.[6]
From wikipedia, which is not the most authorative reference in the world, but at least references other texts. Which you can check out should you have the inclination.
This is correct in classical Latin, but in my experience not true in entomological literature. The push and pull between Latin “purists” and those using the neologisms that have developed through centuries of use of Latin in science writing is a constant ongoing battle.
For example, the hill one of my friends has decided to die on is that the suffix -oid is two syllables in Latin, “oh-id”, but virtually all newer uses of it in science to refer to a thing similar to something else see it pronounced “oyd”. So he pronounces Picoides and Noctuoid and all the other -oid words in the traditional Latin way, even though few scientists know what he’s saying at first. But it’s “technically correct, which is the best kind of correct”. lol
My personal peeve is that “octopi” is a stupid word that shouldn’t exist, because octopus isn’t even Latin, and you can’t just take Greek words, pretend they have Latin endings, and start changing the ending as if it were Latin. But it’s in the dictionary, and we’re speaking English rather than Latin, so I’ve got to deal with it being a thing, even if it’s not a classical Latin thing.
Yeah, I am definitely coming at this from a modern entomological literature viewpoint rather than a classical Latin viewpoint. And honestly, until karoopixie shared the original Latin definition, it hadn’t occurred to me that anyone would talk about one shed from one insect as being multiple things. I guess you could say a head capsule and the shed body exoskeleton are separate items, but it still doesn’t really make sense to me to talk about an empty chrysalis like it’s multiple items. I guess then the correct Latin singular would be exuvium (even if people using Latin back in the day didn’t use it), but I don’t think I’ve seen that much in the modern literature. Google Scholar search gives ~1,700 hits for exuvium and ~3,800 hits for exuvia (both searched with “entomology” in an attempt to rule out unrelated uses).
I care a little bit more about the data/datum issue since you definitely can always have individual data points vs. a group of them, but neither is a hill I’m going to die on
Maybe it would be easier to accept exuviae if you consider that it is analagous to “remains” which is also always plural :-)
Language is a magnificent game, and constantly evolving. One could wax lyrical about all sorts, but that is off-topic, so I shall be Good and not do it
FWIW, I don’t italicize exuvium/exuvia when using them as entomological terms, which in my mind removes them from the realm of classical Latin and into the realm of modern science terms derived from Latin. When the Latin wiki says “Exuvia is a derived singular form, although this is a neologism, and not attested in texts by Roman authors,” I suspect it’s specifically referring to this newer use in entomology. Caligula wouldn’t know what I’m talking about, but a bug nerd would. Haha
But to stay on topic, yeah, unless the observation is for the silk thread on the cremaster, it’s for sure a piece of the original organism, not a construction. Whereas the term for it is a modern construction, not a piece of the original Latin. So the real question is whether the annotation is about entomology or etymology.
Good point! I don’t usually italicize them either; I just followed the style of the first person on the post who used them. I guess that’s another argument for trying not to twitch so much when people say/write “the data shows” or whatever
The chrysalis itself, if not empty, is the actual organism. Once the butterfly has emerged, that’s a molt, as it’s an exoskeleton the organism has left behind.
To add to others’ explanations: some words weirdly enough only come in a plural form, or are usually used in the plural form. Not only in Latin, but also in other languages. English has some of these words, too. Someone mentioned remains, which is a good one. Others are pants and glasses, which is weird, because in the end they’re a single item. In Dutch, we actually use a singular form to describe a single pair of pants or a single set of glasses, and using the plural would indicate several items. Clothes is another one, and exuviae are like the former clothes of the organism.
I think exuvium would be correct, if exuvia was the plural form. But the original word exuviae is plural, so the correct Latin singular should be exuvia. Like rosa and rosae.
I agree with this. If you’ve ever watched a monarch caterpillar do its final skin molt and turn into a chrysalis – the chrysalis is literally the caterpillar. So, organism for green (or other relevant color) chrysalises. Once the butterfly is out of the chrysalis - it’s a molt. If you have an emerging butterfly, molt and organism. If the butterfly is still in the chrysalis but has not yet broken out - I would still label it as an organism bc it hasn’t “molted” the external layer yet.
For butterflies and moths that build cocoons around themselves, I would say the cocoon is a construction.
Technically, the correct pronuciation of “oi” depends on the period of latin. In old latin, “oi” would have been pronounced as a dipthong (equivalent to “oe”). So maybe your friend isn’t being classical enough…