146 FAUNA HAWAIIENSIS 



Fam. ACANTHI I DAE. 



AcANTHiA Fabr. 



Acanthia Fabr., 1775, Syst. Ent. p. 693; Renter, 1896, Act. Soc. Sci. Fenn. xxi. 

 no. 2, p. I ; Kirkaldy, 1S99, Entom. p. 218. 



Salda Fabr., 1803, Syst. Rhyng. p. 103. 



This genus is cosmopolitan, having been recorded from St Helena, New Zealand, 

 and from within the Arctic Circle. A few species frequent heath-lands, though they 

 occur principally at the margins of lakes, ponds, rivers, etc. I have examined 

 29 specimens from our fauna, apparently representing two species, possibly a small 

 proportion of actually existing forms. The genus is certainly of ancient date, though 

 the only fossil records are from Prussian amber (Ligurian Horizon), and is specially 

 interesting as illustrating the probable route of development, in habit and structure, of 

 the cryptoceratous aquatic bugs (excpt Nepa and its allies) from the original terrene 

 Heteroptera. Macropterous and brachypterous forms of both species are found. 



Apex of first (interior) areole of membrane not touching apex of second. Head 

 (with eyes) not nearly as wide as base of pronotuni ; second segment of 

 antennae three times as long as first (7) «7^/(?«.v. White. 



Apex of first areole touching apex of second. Head (with eyes) almost as wide 

 as base of pronotum ; second segment of antennae twice as long as the 

 first (2) oahiiensis, Blackburn. 



(i) Acanthia exidans, White. 



Salda exitlaiis F. B. White, 1878, Ann. Mag. Nat. Hist. (5) i. p. 373. 



Belongs to subgenus Sciodopteriis Amyot and Serville. 



White says " pronoti marginibus angustis lateralibus sordide brunneo-albidis " ; of 

 the five examples examined, this is true of one only, the other four having these lateral 

 margins entirely black. 



Length 4 — 4f mm. 



Hab. "Sparingly from wet moss in or on mountains near the Pali" (Blackburn). 

 — Molokai Mts., 4000 ft. (May and June) ; Kawailoa, from the gulch itself, very far up 

 (March and April). — Oahu, Waialua (March) ; Koolau range (August). — Kauai, 

 VVaimea Mts., 4000 ft. (May), and Koholuamano, 4000 ft. (April), Perkins. 



(2) Acanthia oahiicusis, Blackburn. 



Salda oahiiensis Blackburn, 1889, Proc. Linn. Soc. N. S. W. (2) iii. p. 353. 



Belongs to typical subgenus ; it is extremely variable in colour, but I cannot 

 discover any notable structural differences confined to any of these variations. 



