314 



Leech and Chandler: Coleoptera 



^-J/lh 



Fig. 13:13. Dytiscidae. a, Hygrotus sp., eipileurol margin of 

 adult in ventral view, to show carina near base; b, Bidessonotus 

 sp., meso- and metasternal area of adult, to show metacoxal lines; 

 c, Hydrovatus sp., meso- and metasternal region of adult to show 

 metasternal processes; d, Cybister fimbriolatus, head of larva; 

 e, Dytiscus verticalis, labium of larva (a, F, Balfour-Browne; 

 1940; b, Regimbari, 1895; c, Sharp, 1882; d,e, Wilson, 1923). 



19. Cerci with lateral fringes (fig. 13: 12(f); labium without 



projecting lobes (fig. 13:13e) 



Dytiscus Linnaeus 1 758 



— Cerci lacking lateral fringes (fig. 13:12c); labium with 



2 projecting lobes (fig. 13:11A) 



Hydaticus Leach 1817 



Key to the California Species of Laccophllus 



Adults 



Elytra predominantly yellowish or brownish, variousTy 

 maculate or irrorate with brown, never regularly vittate; 

 male with an arcuate "stridulatory file" of impressed 

 nearly parallel lines on each hind coxal plate, starting 



near apex of metasternum 2 



Brown elytral markings forming regular vittae on at 

 least basal 3rd of elytral disc; hind coxal plates of 

 male without file; Texas, to Riverside and Imperial 



counties quadriline atus Horn 1871 



Metasternum and hind coxal plates black, abdominal 

 sternites largely piceous; elytra nearly uniformly 

 irrorate with brown, vaguely paler laterally and at 

 apex; Qaja California and California to Utah and 



Texas atristernalis Crotch 1873 



Metasternum, hind coxal plates and abdominal sternites 

 yellow or brownish-yellow; elytra irrorate with brown, 



but with sharply defined pale areas at sides, usualh 



on suture behind middle, and at base 3 ] 



Hind coxal lines parallel and well separated anteriorly; 

 elytra narrowly yellow along anterior 2/3 of lateral 

 margins, each elytron usually marked with yellow 

 spots as follows: a su'obasal transverse series, a 

 median lateral spot joined to lateral band, one post- 

 median at suture, a series at apical 3/4, a transverse 

 subapical series; larger species, average length 

 slightly more than 5 mm.; Alaska to 3aja California 



decipiens LeConte 1852 



Hind coxal lines convergent, narrowly separated, 

 in anterior 3rd (fig. 13:9); elytra predominantly yellow 

 in anterior half laterally and basally, and at apex, 

 and with a dark brown area at lateral 2/3; irrorated sec- 

 tions of elytra sharply outlined with darker brown; 

 smaller species, average length 4.75 mm.; Texas to 

 Lower California, Imperial county 



terminalis Sharp 1882 



Genus Macrovatellus 



Adults 



A single species may occur in southern or south' 

 eastern California, since .it has been recorded from 

 the Mexican mainland and Baja California. 



Pronotum much narrower than elytral base, giving a charac- 

 teristic discontinuity of outline; eyes large, prominent; 

 length 5.5 to 6.5 mm mexicanus Sharp 1882 



Fig. 13:14. Dytiscidae. a, Acilius sulcatus, larva; b, Ce/i'no 

 slossoni, adult; c, Bidessus leachi, adult; d, Hydrovatus confer- 

 tus, adult; e, Bidessus shermani, adult (a, Fiori, 1949; b,e, Leng 

 and Mutchler, 1918; c, Leech, 1948; d, Williams, 1936). 



