The Collaborative International Dictionary
Vitrella
Vitrella \Vi*trel"la\, n. [NL., dim. of L. vitrum glass.] (Zo["o]l.) One of the transparent lenslike cells in the ocelli of certain arthropods.
Wiktionary
vitrella
n. (context zoology English) One of the transparent lens-like cells in the ocellus of certain arthropods.