174 [August, 



States adjacent, i. e., New Mexico, N. americana is widely distributed 

 over Mexico, the Antilles, and the Northern two-thirds of South 

 America. 



The species of both genera, although water inhabitants, usually 

 leave the element during the night, either for " love meetings," or 

 merely for change of residence. They are captured with nets, dried, 

 and (according to Yirlet d'Aoust) sold as " bird food " under the name 

 of "moschitos," although Clavigero states that the Mexicans eat them 

 dried and dressed with saltpetre ! 



The minute ova, however, are employed entirely as a fillip to 

 human appetites, and therefore merit a closer consideration. The 

 shape and external structure of the two kinds are very different. The 

 ova of N. americana are oblong-oval, very slightly broader at one end, 

 a,nd the surface is reticulated with irregular pentagons and hexagons, 

 the whole surface being minutely and densely but superficially punc- 

 tured, I have not seen any of these ova in situ, but they appear to 

 be rather loosely fastened by a " gummy " substance to the external 

 surface of water plants, &c., as in the case, under unfavourable cir- 

 cumstances with the British N. glauca, although the latter usually 

 partially inserts them in an incision made in the stem of some suitable 

 plant. Now, as Notonecta is most certainly derived from a Corixid 

 stock, and as the Gorixce do not employ the incision method, it is 

 probable that this is a fairly recent acquisition on the part of N. 

 glauca. 



The ova of C. mercenaria, which occur close together in large 

 numbers, are much smaller, and irregularly ovate ; they are always 

 connected by an extensile, translucent, colourless " stalk " to a large 

 disc which is affixed to a leaf or plant-stem. There is no surface 

 structure (except a slight rugosity) visible with a one-quarter inch 

 objective, although Meczinkov describes and figures (Zeitschr. fiir 

 Wiss. Zool., xvi, p, 422, pi. xxvi, fig. 18 [1866]) a reticulation composed 

 of regular (!) hexagons, in an unnamed European species (probably 

 G. Oeqffroyi) . At the proper season bundles of rushes are placed in 

 the lake shallows, and upon these the ova— named by the Mexicans 

 "Axayacatl" or "waterface" — are deposited, gathered by the natives 

 and made with meal into cakes ; these are eaten au naturel or with 

 green chilies ! They are also cooked without further preparation, 

 having then the appearance of fish roe, when they are called " Ahua- 

 uhtli " or " waterwheat ;" they are said to have a delicate flavour and 

 not to be disdained at fashionable tables, Virlet d'Aoust comparing it 

 to Caviare. 



