“The insects which principally produce this animal farinha of Mexico,” says a writer in the Journal de Pharmacie, “are two species of the genus _Corixa_ of Geoffroy, hemipterous (heteropterous) insects of the family of water-bugs. One of the species has been described by M. Guerin Méneville as new, and has been named by him _Corixa femorata_: the other, identified in 1831 by Thomas Say as one of those sold in the market at Mexico, bears the name of _Corixa mercenaria_. The eggs of these two species are attached in innumerable quantities to the triangular leaves of the carex forming the bundles which are deposited in the waters. They are of an oval form with a protuberance at one end and a pedicle at the other extremity, by means of which they are fixed to a small round disk, which the mother cements to the leaf. Among these eggs, which are grouped closely together, there are found others, which are larger, of a long and cylindrical form, and which are fixed to the same leaves. These belong to another larger insect, a species of _Notonecta_, which M. Guerin Méneville has named _Notonecta unifasciata_.” It appears from M. Virlet d’Aoust, that in October the lakes of Chalco and Texcuco, which border on the City of Mexico, are haunted by millions of “small flies,” which, after dancing in the air, plunge down into the water, to the depth of several feet, and deposit their eggs at the bottom. “The eggs of these insects are called hautle (haoutle) by the Mexican Indians, who collect them in great numbers, and with whom they appear to be a favorite article of food. They are prepared in various ways, but usually made into cakes, which are eaten with a sauce flavored with chillies.”[926] Rev. Thomas Smith enumerates the following insects as eaten by the ancient Mexicans: The _Atelepitz_, “a marsh beetle, resembling in shape and size the flying beetles, having four (?) feet, and covered with a hard shell.” The _Atopinan_, “a marsh grasshopper of a dark color and great size, being no less than six inches long and two broad.”(!) The _Ahuihuitla_, “a worm which inhabits the Mexican lakes, four inches long, and of the thickness of a goose quill, of a tawny color on the upper part of the body, and white upon the under part; it stings with its tail, which is hard and poisonous.” And the _Ocuiliztac_, “a black marsh worm, which becomes white on being roasted.”[927] ORDER IX. DIPTERA. Culicidæ--Gnats.[928] Concerning the generation of Gnats, Moufet says: “Countrey people suppose them, and that not improbably, to be procreated from some corrupt moisture of the earth.”[929]