A moth name, not a craft word
In ordinary English, hyphantria is not a word for cloth, looms, or anyone who works at them. Dictionaries treat it as a capitalized noun: a genus of tiger moths whose hairy, social caterpillars can defoliate trees. The species readers are most likely to meet is the fall webworm, now Hyphantria cunea. Late in summer the larvae spin communal silk tents over the leaves of elms, apples, and other hosts and feed together under that cover. That habit is why the name was chosen.
The origin of the word hyphantria is scientific. It did not descend through Old English, and it was not borrowed from French or Latin in everyday speech. It was coined in 1841 as a New Latin genus, then kept in English entomology and, later, in general dictionaries as a taxonomic label.
Harris and the weaver
Thaddeus William Harris, a Massachusetts entomologist writing for farmers as much as for specialists, first placed the insect in Arctia. In the New England Farmer he had already given the species the Latin epithet textor, weaver, because of the caterpillars’ well-known webbing. In his 1841 Report on the Insects of Massachusetts, Injurious to Vegetation, he proposed a split. If the moth left Arctia, the new genus should be Hyphantria, which he presented as a Greek name for weaver. He intended to put with it the southern many-spotted ermine moth, then Arctia punctatissima, because it shared the same nesting habit.
Catalogues of Lepidoptera still date the genus to that report, on page 255. The type species was later fixed as Hyphantria textor. That combination is now a junior synonym of Hyphantria cunea, a moth Drury had already figured in the eighteenth century, named in 1773. The genus itself stands. English therefore absorbed the word as a proper scientific name, not as a common noun that ever meant weaver in the street or the workshop.
Harris’s own explanation was short. He did not unpack Greek gender or cite a lexicon. English dictionaries are tighter: New Latin Hyphantria is taken from Greek hyphantria, a female weaver, the feminine counterpart of hyphantēs, a weaver. The two accounts do not really clash. Harris needed a Greek weaver for a moth whose young spin a tent; the dictionaries name the exact noun he reached for.
From the verb to the agent
Behind both Greek nouns sits the verb hyphainein, to weave. Classical lexica list hyphantēs as weaver and hyphantria as the feminine form, in later authors rather than in Homeric epic. The ending -tria marks a female agent. English once did something similar with webster, originally a woman who wove, but that suffix is Germanic and unrelated. The resemblance is only the shared idea of a feminine worker-name.
The verb belongs to an Indo-European root of weaving, reconstructed as webh- or, with a laryngeal, h1webh-. Handbooks disagree on the notation, not on the family. Greek also has hyphē, a web. English hypha, the threadlike filament of a fungus, is a later scientific borrowing from that noun, so the moth genus and the mycological term are cousins twice removed, not the same coinage.
Native English weave and web come down the Germanic branch of the same root: Old English wefan and webb, with Dutch weven and German weben beside them. Farther out sit Sanskrit forms meaning to lace or bind together, and Persian baftan, to weave. Those are genuine cognates of the Greek verb. They are not the source of the English moth name; they show how old the weaving vocabulary is.
Latin textor, Harris’s species name, also means weaver, but it is not kin to hyphantria. It derives from texere, to weave, on a different Indo-European root. The pairing is semantic, not genealogical: Greek weaver for the genus, Latin weaver for the species, both aimed at the silk nest.
A sense that barely moved
Because the word entered English as a genus, its meaning has hardly shifted. Nineteenth-century entomology already used it for the fall webworm group. Modern dictionaries still define it as a genus of arctiid moths with hairy social larvae that damage trees. What has moved is the higher classification around it. Older lists placed the moths in Arctiidae; current taxonomy puts Hyphantria in Erebidae, subfamily Arctiinae. That is a change of family assignment, not of English sense.
The name did not become a metaphor for a human weaver, and it picked up no slang. There is no separate popular etymology to unpick, and no folk story attached to the spelling. If a first-attestation date in non-technical English is wanted beyond Harris, dictionaries do not supply a later street use; they simply record the capitalized genus. Etymology sites that cover weave and hypha often skip this headword altogether, which is a fair sign that the trail lives in New Latin scientific vocabulary and in the Greek lexicon, not in the history of common English.
Modern Greek still uses υφάντρια or υφάντρα for a woman who weaves. That is the same noun Harris borrowed, still alive as an occupation word. English froze the form as a moth.
Two weavers, one tent
The leftover fact is the double label. Harris first called the caterpillar a weaver in Latin, then named the genus with the Greek feminine for the same trade. A fall webworm tent on an elm or apple is the behavior that selected both. The everyday English word web in the common name is a true cognate of the Greek verb; the genus carries the Greek agent. The moth never needed a new meaning in English. It needed a name that already meant someone who weaves.