90 INSECTA MADERENSIA. 



The genus Parnus, concerning the location of which entomologists are stUl so 

 much divided, may be readily known by the subcylindi-ical, villose bodies of the 

 few species which compose it, by their slender elongated legs and unarmed tibiae, 

 and by their subnatatorial habits, — their legs not being formed for s-ndmming, but 

 for walking on muddy banks, or adhering to the submerged aquatic plants of 

 ditches and pools. They are of an extremely sluggish natiuT, and possess the power 

 of remaining a great length of time imder water, theii- woolly smfaces enabling 

 them to retain a sufficient quantity of air for respii-ation dm-ing submersion. 



71. Parnus prolifericomis. 



P. subcylindrico-oblongus fusco-uiger, infra albido-holosericeus, supra olivaceo-v'illosus, elytris obso- 



Ictissime subpunctato-striatis, tarsis elongatis piceis. 



Long. Corp. lin. 2-2j. 



Parnus prolifericomis, Fab. Ent. Si/st. i. 245 (1792). 



, GyU. Ins. Suec. i. 139 (1808). 



, Steph. III. Brit. Ent. ii. 103 (1829). 



, Zett. Ins. Lap. 125 (1840). 



Habitat in aqiiis quietis Maderje, plantis aquaticis adhferens, vel sub lapidibus ad margiues rivulorum, 

 toto anno frequens. 



P. elongate, subcylindrical-oblong, brownish-black with a just perceptibly sneous tinge; densely 

 clothed beneath with a short, whitish, and above wth a lougj woolly, olivaceous pubescence ; 

 minutely punctured. Prothorax convex on the disk; and with an impressed longitudinal line 

 on either side. Elytra very obsoletely striated, the strife having obscure indications of being 

 punctured. 7am long and piceous. 



Abundant at aU seasons of the year at the edges of the pools and streams of 

 Madcu-a, ranging fi-om about 1000 to 5000 feet above the sea. My own specimens 

 are principally from the Cm-ral das Romeiras, Santa i\jina, the Cruzinhas, and the 

 Panal ; but there is scarcely a district in the island in which I have not observed 

 it to exist. It is a common insect tlu'oughout Eiu'ope and Algeria ; and the 

 Madeii"an specimens do not appear to differ in any respect fi'om the ordinary type. 



Farn. 5. HYDROPHILIDiE. 



Genus 30. OCHTHEBIUS. 



Leach, Zool. Miseell. iii. 91 (1817). 



Corpus niinutum, elongato-ovatum : prothorace subcordato, plus minusve foveolato : alis amplis. 

 Antenna 9-articulat;e brcvissimae, articuhs primo et secundo robustis, illo elongate flexuoso, hoc 

 breviore subovato, tertio gracillimo subspatulato, quarto brevi minutissimo, reliquis clavam 

 oblongam jjubescentem quinque-artieulatam apicc obtusam efficicntibus. Labrum transvcrsum, 

 antice leviter euiarginatum cihatum. Mandibutte breves latir, apice fissK, basi membranacea; 



