AffahllS.] ADEPIIAGA. 197 



unequtil, the front one being moderately long, and the hinder one elongate 

 and much dilated behind ; female duller than male with the striae finer 

 and denser. Long, 10, lat. 5| mm. 



Ponds and stagnant water generally ; very common and widely distributed through- 

 out the kingdom. 



This species is extremely variable in sculpture ; in the highland dis- 

 tricts of Britain {Snowdon, NoHh of England, and Scotch Highlands) 

 the specimens become smaller, and of a narrower, more oblong and de- 

 pressed form ; the males also become more shining and smooth, and one 

 form of the females much duller, so that the disparity between the sexes 

 appears much greater than in the type form : this is the Arjabus Solieri, 

 Aube, and is called by Dr. Sharp " tlie dimorphic Alpine form" of ^. 

 bipustulatu.'^ ; it appears distinct at first sight, but is connected with the 

 ordinary temperate European form by every intermediate gradation ; the 

 colour is also variable, the elytra being sometimes reddish. 



PXiATAMBUS, Thomson. 



This genus comprises three species, one from Asia i\rinor and the 

 Caucasus, anotlier from Japan, and the third occurring in Europe from 

 Sweden and Finland to Spain. 



A. xnaculatus, L. Oval, rather convex ; head red with more or 

 less distinct dark markings, thorax reddish testaceous with anterior and 

 posterior margins more or less broadly black ; elytra very variously 

 coloured, ranging from quite dark with margins and a few spots testa- 

 ceous, to testaceous with more or less regular dark markings, which are 

 usually broad, confluent, and longitudinally arranged; thorax with 

 lateral margins fine, posterior angles acute ; elytra smoother towards 

 base than at apex ; prosternal process broad, acuminate at apex ; male 

 with front and middle tarsi slightly thickened ; the sculpture and colour 

 is variable, but the disparity is not sexual. Long. 7|-8, lat. 4j mm. 



Common and widely distributed in running streams throughout England and Wales; 

 Scotland, common tliroughout the greater part of the country ; a small dark variety 

 occurs at Aylsham (T. Wood), unaccompanied by the type, but these forms are more 

 usually found in Scotland (liracmar, &c.). 



ZZ.VBIUS, Erichson. 



This genus comprises upwards of thirty species, which are peculiar to 

 Europe, JS^orth and Central Asia, Japan, and North America ; seven of 

 tliese are British, two or three of which rc(|uire some care to distinguish 



them. 



The larva of I/i/bius fenesfralus is figured by Schiijdte (ii., PI. vi., Fig. 9): in 

 shape and gcnenil appearance it ^o closely resembles the h\v\n of J'/'i/(imhiis vidciiln/ux 

 tli;it there is hardly lued of a sejii'.rate description : the head is rather more (piadratc, 

 and the thorax longer and sonicwliat dill'erently hl)a))t'd, having the base truncate ainl 

 nut strongly sinuate; the seventh and eighth abdominal segments are very much 



