PotaminusJ] CLAVICOKNIA. 381 



several from North America ; the New World species are remarkable for 

 being covered with stony incrustations; they closely resemble Parnus, 

 but may be known superficially by their longer legs and the absence 

 of engraved lateral thoracic lines ; our single species is a very scarce 

 insect, and most of the specimens in our collections have been taken 

 in the Dove in the same locality as Macronychus. 



P. substriatus, Mull. (Dry ops Dumerilii, Latr. et auct.). Of the 

 same shape as Parnus prolifericornis, but a little more convex, dark 

 reddish-brown, with the head and thorax darker, sometimes pitchy-brown 

 or almost pitchy-black, the thorax being lighter at margins ; the whole 

 surface, especially of the elytra, is covered with very thick yellowish, 

 almost golden pubescence, which is often less evident on thorax ; antennae 

 very short ; thorax a little narrower than elytra, broader than long, with 

 sides only slightly rounded and rather strongly margined, very thickly 

 and finely punctured, anterior angles produced ; scutelium rather large ; 

 elytra convex, with distinct finely punctured striae, interstices somewhat 

 raised ; under-side red-brown ; legs long, reddish, with femora darker. 

 L. 4-5 mm. 



Uuder clods submerged at the sides of streams, and under submerged stones, but not 

 apparently under stumps or logs ; rare ; River Dove, near Burton-on-Trent ; Scar- 

 borough ; banks of Waudle near Garrat Greeu arid in Yorkshire (Stephens). 



PARNUS, Fabricius (Dryops, Olivier nee Leach). 



This genus contains sixteen species, of which all are found in the 

 Mediterranean region except one which has been recorded from Brazil ; 

 other species, however, exist in Tropical America which have not been 

 described ; according to the Biologia Centrali-Americana, the New 

 World species all have the second joint of the antennae much less 

 developed than is the case with the European species, and the club 

 consists distinctly of nine joints, whereas in the Old World species only 

 seven or eight can be distinguished ; this character, however, cannot be 

 regarded as generic, as the point still appears to be disputed, some 

 authors considering our species to have the antennae 11- jointed. 



I. Elytra very finely punctured, with scarcely any traces 



of striae ; pubescence yellowish-grey P. PROLIFEBICOBNIS, F. 



II. Elytra more or less strongly and distinctly punctured. 

 i. Elytra with traces of striae at base only ; pubescence 



dark P. AUEICTJIATUS, Pane. 



5i. Elytra with striae complete and distinct ; pubescence 



greyish P. ALG-IRICUS, Lucas 



(striatellus, Fairm.). 



iii. Elytra without trace of striae ; pubescence golden- 

 yellow P. NITIDTJLUS, Heer. 



P. prolifericornis, F. Elongate, subcylindrical, very finely punc- 

 tured fuscous black, thickly clothed with short erect, yellowish-grey 



