714 



On Aquatic Carnivorous Coleoptera or Dijtiscidw. 



The front tarsi of the male are rather small for the size of the insect, being about 

 OS m.m. in the transverse direction ; beneath the palettes are narrow, the 

 pubescent area large, and the basal fringing hairs fine and but little developed. On 

 the middle tarsi the basal joint bears beneath a very large patch of elongate, dense 

 sexual hairs, they cover the whole of the joint and greatly overlap the following 

 one. 



I have seen only a single individual of this species. It is the giant of the 

 Dytiscidae, much exceeding in bulk the largest individuals of Cybister giganteus. 

 It is closely allied to that species but is distinguished by its larger size, and the 

 male is also conspicuous by the great development of the sexual pubescence on the 

 basal joint of the intermediate foot. The swimming legs are very powerful, their 

 femora measuring b\ m.m. across. 



Brazil, (coll. Saunders). 1114. 



I. 79.— Genus CYBISTER. 



Coxal lines present ; unguicular cleft narrow and angular at base ; only a single 

 claw on the hind tarsus in the male sex; (the females also have only a single claw 

 but in some cases a very rudimentary second claw exists). 



The numerous species* are widely distributed, but do not occur in South 

 America. They may be arranged in six groups as follows : — 



£-3 



o 



.S TJ 



" o 



2 o 

 -a © 



-a 



"i !=> . 

 a ° s 



o *-^ -* 



■*^ ^ M ^ 



\ Elytra with yellow latei-al stripe ; male with axillar 



^ -t^ "3 "^ I rugse. (North American species.) 



} 



g .s g 3 . I Elj-tra without yellow lateral stripe ; male without 1 

 ^ = S g 3 [ axillar ruga;. (Asiatic and African species.) j 



• • •( 



2§5 



O «n 5 



axillar ruga;. (Asiatic and African species.) 

 El3rtra without yellow lateral stripe, . 



^ ^ a 



© rt ^ 



"c5 - & . 



a ^ ^ 03 



Elji;ra with yellow lateral stripe extending to and ( 

 including the epipleura. | 



Elytra with yellow lateral stripe, wliich does not ) 

 extend to or include the epipleura. J 



The feiaale as well a-s the male furnished ^vith swimming hairs on each side I 

 of the hind tarsi. \ 



Group 1. 

 Nos. 1119 to 1121. 



Group 2. 

 Nos. 1122 to 1134. 



Group 3. 

 Nos. 1135 to 1139. 



Grouj) 4. 

 Nos. 1140 to 1151. 



Group 5. 

 Nos. 1152 to 1168. 



Group 6. 

 Nos?. 1169 to 1171. 



* The descriptions cited in the following list refer probably in part to species unknown to me : — 

 Cybister auritus, Gei-st. (No. 1275, huj. op.) ? = No. 1280 ; Africa. — Cybister dejeani, Aube (No. 1276) j 

 India. — Cybister jordanLs, Reiche, (No. 1279) ? No. 1169 var.; Syria. — Cybister marginicollis. Boh. 

 (No. 1280), near No. 1129; Caffraria. — Cybister olivieri. Crotch. (No. 1281); North America. — 

 Cybister vuhieratus, Klug. (No. 1283) ] No. 1 133 var. ; Arabia. — Dytiscus extenuans, Walk. (No. 1289) ; 

 Ceylon. — Dytiscus tataricus, Gebl. (No. 1295) ?=No. 1169; Tartary. — Trochalus rugulosus, Eedt. 

 (No. 1509) ] near No. 1167 ; India.— Trogus natalensis, Wehncke (No. 1510) 1 near No. 1148 ; Natal 

 — The systematic position of the following is not quite clear : — Cybister prostevno-\iridis, Orm. (No. 

 1 282) ; ? South America. 



