344 ENTOMOLOGICAL SOCIETY 



edge. Like the imago, it does not swim, and when detached from 

 the debris to which it clings sinks helplessly to the bottom or 

 is swept away by the current. 



The nature of its food was not discovered, but the large size 

 and form of the buccal cavity shows that it masticates its food and, 

 if carnivorous, is not rapacious. 



Described from seventeen alcoholic specimens collected in City 

 Canon, Utah, June 26, 1891, and one specimen from American 

 Fork Canon, Utah ; the last is a dark, strongly chitinized speci 

 men, and 'has turgid elevations, above and below, on the expla- 

 nate margins of all the segments. 



The larva of Amphizoa presents a structure severely simple, 

 yet well differentiated in all its parts, and, like the imago, gives 

 the impression of a terrestrial beetle with amphibious or 

 semiaquatic habits. In general appearance it recalls the larva 01 

 Cychrus. The solid, non-suctorial jaws, lobed maxillae, and 

 ambulatory legs show close alliance with the caraboid type, and 

 effectively separate it from the DytiscidaB. An approach to the 

 latter family is made in the concealed ninth joint of the abdomen 

 and the terminal spiracles of the eighth abdominal segment, 

 structures adapted to an aquatic life. With the Old World 

 genus Pelobius the larva of Amphizoa is strikingly allied in 

 many structural details. The suctorial jaws of the Dytiscidas 

 are wanting in both genera. The larva of Pelobius, being 

 wholly aquatic, breathes by means of fasciculate branchiae, and 

 the obsolete spiracles are represented by buttons. In Am 

 phizoa there are no branchiae in the adult larva, and the animal 

 breathes by means of a pair of spiracles at the end of the body. 

 But the structure of the abdomen is essentially the same, the 

 eighth segment being terminal in both genera. This segment in 

 Amphizoa bears air-breathing spiracles, is slightly prolonged 

 and capable of being protruded into the atmosphere from shallow 

 water, but in Pelobius it is greatly prolonged into a natatory 

 stylus. The cerci in the two genera arise in a precisely similar 

 manner from the rudimentary ninth segment, and conform to the 

 differences in their habits of life, being short spiny processes, as 

 sisting in progression in Amphizoa, but in Pelobius developed 

 into long ciliated natatory organs. 



The larval characters in Amphizoa indicate an ancient syn 

 thetic type, having alliances with several existing families of 

 coleoptera, but sufficiently isolated to forbid its entrance into any 

 one of them. 



Schiodte in his classification of coleopterous larvae* has clearly 

 pointed out the fundamental differences which separate the 



*De Met. Eleuth. Observ. No. 6 (Kroyer Naturh. Tidsskrift, Vol. VIII, 

 1872, pp. 174-178. 



