432 NATURAL HISTORY OF ARTHROPODS. 



still, the lake has a look as of oil and is not easily disturbed. The water feels slippery 

 to the touch, and will wash grease from the hands or from clothes, cold, more readily 

 than common soap-suds will when hot. It is said that no fish or reptile lives in it, but 

 it swarms with countless millions of larvae, that develop into flies which rest on the 

 surface of the water, as well as cover everything on the immediate shore. The num- 

 ber and quantities of these flies and larvae are absolutely incredible. They drift up in 

 heaps along the shore, and hundreds of bushels could be collected ! They only grow 

 at certain seasons of the year, and then Indians come from far and near to gather 

 them for food. The worms are dried in the sun, the shell rubbed off by hand, when 

 a yellowish kernel remains, like a small yellowish grain of rice. This is oily, very 

 nutritious, and not unpleasant to the taste, and, under the name of koo-chah-bee (so 

 pronounced), forms a very important article of food. The Indians gave me some of 

 it ; it does not taste badly, and, if one were ignorant of its origin, it would make nice 

 soup. It tastes more like patent ' meat biscuit ' than anything else I can compare it 

 with. 



" I will say in addition that koo-chah-bee was rather palatable. The waves cast 

 these larvae in little windrows on the shore ; the quantity is large, the chief difficulty 

 in collecting is to get it as free from sand as possible, and it is then dried on clothing 

 or blankets. My guide, an old hunter there, told me that everything fattens in the 

 season of the koo-chah-bee / that ducks get very fat, but their flesh tastes unpleasantly 

 from it, and that the Indians get fat and sleek. There are many gulls about the lake 

 at that season. 



" The flies settle on twigs, spires of grass, etc., until nothing of the perch can be 

 seen, merely a wand of closely clinging flies. They also at times rest on the water 

 in great numbers." 



Another species, JZphydra hians, is found in equally great quantities in Lake Tex- 

 coco, near the city of Mexico, and Professor Penafiel, who has carefully studied the 

 subject, has sent the writer the following notes concerning them : " It is of the eggs 

 of this insect, I believe, that the greater part of the food products of this lake, 

 known as Ahuatle, is composed, and which is now used by the natives, who have pre- 

 served the customs of the ancient Aztecs in this same valley of Mexico. The natives 

 cultivate in Lake Chalco a species of sedge ( Cyperus longifolius) on which the flies 

 will deposit their eggs in abundance. This sedge they make into bundles, which they 

 carry to the Lake of Texcoco and let float upon the water till they are covered with 

 eggs ; they then remove and dry them, and separate the eggs by beating over a large 

 piece of cloth. The eggs are then cleaned and ground into flour, w r hich is called 



Ahuatle. This food is deemed suitable for those 

 days in which the religious observances prohibit 

 the iise of flesh. It is prepared by mixing with 

 hen's eggs and fried with fat into small cakes. 

 The taste is similar to that of caviare, though 

 hardly as pleasant. 



The larvae are also used as food, under the 

 name of Puxi. 



FIG. 545. Drosophiia, fruit-fly,- , larva. The larvae of species of Drosophttci are fre- 



quently found in decaying fruit, preserves, etc. 



The flies are but three or four millimeters long, and are of a yellowish color with trans- 

 parent wings. 



