300 



Leech and Chandler: Coleoptera 



with similar habits in other parts of the world: A'epus 

 from the coasts of Europe and the island of Madeira; 

 Aepopsis from England, Spain, Morocco, etc., Thalas- 

 sobius from Chile; lllaphanus from the southeast coast 

 of Australia. In A'epus some of the tracheae are ex- 

 panded into large internal air reservoirs, but the 

 structure of Thalassotrechus has not been reported 

 upon. 



Kay to the California Species of Thalassotrechus 



Adults 



1. Head, pronotum and elytra rufotestaceous; Santa 



Barbara County barbarae (Horn) 1892 



— Head and pronotum rufotestaceous, elytra black except 

 narrow marginal bead, and epipleura; Dillon's Beach, 

 Marin County; Moss Beach, San Mateo County; Carmel 



and Pacific Beach, Monterey County . , 



nigripennis Van Dyke 191 8 



REFERENCE 



VAN DYKE, E. C. 



1918. New Inter-tidal rock-dwelling Coleoptera from 

 California. Ent. News, 29:303-308. 



Family AMPHIZOIDAE 



The amphizoids are sluggish beetles, 11 to 15 mm. 

 long, to be found in many streams and rivers. All 

 belong to the single genus Amphizoa. The adults 

 (fig. 13:1a) are black to reddish-brown and resemble 

 certain Tenebrionidae; in fact, one kind was described 

 as a new genus and species of that family. The larvae 

 (fig. 13:2) are also aquatic, and at a glance resemble 

 those of the cychrine carabids and some silphids. 

 Both adults and larvae crawl but do not swim. They 

 occur under stones and in trash along the edges of 

 streams and rivers, and in log jams, eddies, and 

 backwaters. Darlington (1929) says: "Amphizoa 

 emits an odor which is rather pleasant, at least to the 

 collector, and which Horn compares to that of decay- 

 ing wood. The beetles also exude a thickish, yellow 

 fluid from the joints, so that they leave a cigarette- 

 like stain on the fingers." However, Edwards (1953) 

 reports that the yellowish fluid is actually "dis- 

 charged from the anus and is immediately spread over 

 the entire abdominal surface by the thfeshing about 

 of the hind legs." 



Relationships. — The family Amphizoidae belongs to 

 the Adephaga and is of caraboid stock. It shows 

 relationships with the Carabidae and Dytiscidae but 

 is more closely allied to the Old World family Hygrobi- 

 idae. Like this last it is distinguished from the 

 Dytiscidae by having a transverse, triangular ante- 

 coxal sclerite separated by a well-marked suture. It 

 differs from the Hygrobiidae, but resembles some 

 Dytiscidae, in that the metasternal episterna reach 

 the middle coxal cavities, and it differs from both in 

 that the legs are ambulatory and not specialized for 

 swimming. The wings (fig. 13:16) are venationally 

 like those of the Dytiscidae. The larvae resemble 



metosternum 

 elytron --.. 



metasternal 

 epimeron "" 



1st abdomina 

 sternite 



hind coxa 



Fig. 13:1. a, adult of Amphizoa inso/ens; b, wing of Amphizoa 

 lecontei; c, eighth abdominal tergite of larva of Amphizoa If 

 contei, showing large spiracles; d, ventral aspect of Calosoma 

 sem/'/aeve to show body parts; e, Omophron tanneri proximum, 

 adult (a, Sharp, 1882; b, Edwards, 1950; c, Hubbard, 1892; d, 

 Essig, 1926; e. Chandler, 1941). 



those of some carabids, but have eight instead of 

 nine or ten visible segments; they differ from dytiscid 

 larvae in having nonsuctorial mandibles. 



Hubbard (1892) thought that both larvae and adults 



