These eggs are deposited at the edge of the lake, and the Indians fish them out and sell them in the market-place.

So large is the quantity of these eggs, that at a spot where a little stream deposits carbonate of lime, a peculiar kind of travertine is forming which consists of masses of them imbedded in tho calcareous deposit.
The flies[14] which produce these eggs are called by the Mexicans "_axayacatl_" or "water-face." There was a celebrated Aztec king who was called Axayacatl; and his name is indicated in the picture-writings by a drawing of a man's face covered with water.

The eggs themselves are sold in cakes in the market, pounded and cooked, and also in lumps _au naturel_, forming a substance like the roe of a fish.

This is known by the characteristic name of "_ahuauhtli_", that is "water-wheat."[15] The last thing we did at Tezcuco, was to witness the laying down of a new line of water-pipes for the saltworks.

This I mention because of the pipes, which were exactly those introduced into Spain by the Moors and brought here by tho Spaniards.