Miscellaneous. 79 



Named in compliment to W. H. Benson, Esq., who has contri- 

 buted so much to our knowledge of Indian land-shells. 



WiLKiNSON^A MoussoNiANA, Chitty. 



Hab. Yallahs Hill. 



Form, subdiscoidal. Colour, white, semitransparent. Sculpture, 

 22 lines, four of which are very slightly stronger than the rest, 

 lowest most strong and prominent ; on the upper whorls, 7. Spire, 

 slightly elevated, with convex outlines. Whorls, 3^, slightly rounded, 

 with a light suture. Aperture, slightly expanded and depressed 

 below, more than a semicircle. Labrum, thickened and reflected, 

 double above, very slightly scolloped by the four stronger carinae, or 

 rather the labrum is produced in straight lines to meet each stronger 

 carina, forming three straight lines scarcely pectinated, in octagonal 

 shape, moderately and roundly produced above from the body- whorl. 

 Labium, rather curved, below the plane of the labrum above, mode- 

 rately detached from the body-whorl. Umbilicus, deep. Labral 

 lamella, sharply, finely and uniformly produced. Operculum, slightly 

 concave, smooth, with ? two strong rounded carinse vertically cross- 

 ing the hollow. 



Height 0-035, greatest breadth 0*058, least breadth 0-042. 



Named in compliment to Prof. A. H. Mousson of Zurich, Switzerland. 



[To be continued.] 



MISCELLANEOUS. 



On some Eggs of Insects employed as Human Food, and giving rise 

 to the formation of Oolites in Lacustrine Limestones in Mexico. 

 By M. ViRLET d'Aoust. 

 The author states that the bottom of the lakes of Chalco and 

 Tezcuco, which border the city of Mexico, consists of a calcareous 

 mud, of a whitish-grey colour, the formation of which is still in pro- 

 gress, as indicated by the remains of human industry which occur in 

 it. Whenever he observed these calcareous deposits uncovered by 

 water, he was struck with finding that they constituted oolites exactly 

 identical in appearance, and in the form and size of the grains, with 

 those of the Jurassic system. On mentioning this circumstance 

 to Mr. J. C. Bowring, director of the salt-works of Tezcuco, in whose 

 trenches the oolitic structure was clearly exhibited, he stated that 

 these oolites were formed by the eggs of insects, which are subse- 

 quently incrusted by the calcareous concretions constantly deposited 

 by the waters of the lake. 



' It appears, from the further statements of the author, that, espe- 

 cially in October, the lake is haunted by millions of small flies, which 

 after dancing in the air, plunge down into the shallower parts of the 

 water to a 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 favourite article of food. They are prepared in various 

 ways, but are usually made into cakes, which are eaten with a sauce 

 flavoured with chillies. 



