380 CLAVICORNIA. \Macr onychut. 



subsequently been taken in numbers by Mr. Harris, Mr. E. Brown, and 

 Mr. W. Garneys, and sparingly by Mr. Blatch and myself; no other 

 British locality is known, but there must be many others, as an aquatic 

 insect is not likely to occur in a single stream in the centre of England 

 and in no other. 



The larva of M. quadrituherculatus is described and figured by Perris, Ann. Fr. 

 1863, p. 621, t. 14, fig. 1 15 ; it is of an obscure dirty-grey colour above with a badly 

 limited lighter band on each side of the central line, nnder-side pale; upper surface 

 rough ; form elongate, a little broader in front than behind, gradually narrowed to 

 apex; head small, much narrower than thorax ; antennse short ; prothorax very large, 

 nearly as long us the next three segments together, nieso- and metathorax and the 

 first eight abdominal segments of about equal length, ninth abdominal scgtn'ent elon- 

 g;iU', narrowed to apex, which is emarginate and furnished with long setse ; legs 

 moderately long, terminating in a single stout claw. 



XIX. quadrituberculatus, Mull. Elongate, narrow, black, some- 

 times very faintly metallic, front margin of thorax reddish ; under-side 

 "and legs pitchy ; head rather long ; forehead very thickly and rugosely 

 punctured ; thorax somewhat narrower than elytra, longer than broad, 

 narrower in front, finely margined at sides, very finely punctured, with 

 two distinct tubercles at base ; elytra with distinctly punctured strise 

 which become gradually weaker towards apex, second interstice on each 

 side near base raised into a strong longitudinal tubercle which is furnished 

 with a distinct crest of thick upright setae ; the interstices are more or 

 less setose ; legs very long, tarsi curved and furnished with strong claws. 

 L. 2|-3 mm. 



On submerged logs and stumps ; has only occurred in one locality in Britain, viz. 

 the River Dove near its confluence with the Trent between Willington near Repton 

 and Burton-on-Trent. 



PARNINA. 



Under this tribe Dr. Horn includes the Larina, in which case the 

 character of the short antennse above given will not hold good except for 

 our native species, as the antennae in Lara are long and slender ; the 

 latter genus, however, must, apparently, be separated from Parnus and 

 its allies ; the two British species Parnus and Potaminus are rather long, 

 oblong, subcylindrical insects, with long slender legs, and with the antennae 

 scarcely apparent when the insect is viewed from above ; the upper 

 surface is thickly clothed witih yellowish or greyish or sometimes fuscous 

 pubescence ; they may be distinguished as follows : 



I. Intermediate coxae separate ; thorax without impressed 



lines at sides PoTAMiNUS, Sturm. 



II. Intermediate coxa contiguous; thorax with impressed 



lines at sides PARNTTS, F. 



POTA1WCINUS, Sturm (Dryops, Leach, nee Olivier). 

 This genus contains one species from Europe, one from Java, and 



