British Species of \\i\\\\}\{Xii. ]13 



I expect tliat it i.s inon; widely rlistributcd than tlic records 

 indicate. The only Irisli locality i.s in (lo. Down, where it 

 occurs fairly conitnonly in pools on the salt-marsh at Kiiloui,^h. 

 Tiie only Scottish records are lor Dutnli ics and Kirkcudbri^^lit, 

 while tlie English records nie for Durham, Yorks N.I'j., 

 Norlolk E., Suffolk E., Kent W., and Hants S., and 

 Wai wick, wlierc it is dcscriljcd as bein^ " local and rare at 

 Knowlf/' j)robably erroneously (6). 



\\'ith rr_i;ard to ihe characters for determining the species, 

 I have drawn up a short summary, which may be useful, 

 aIthou<;h, as 1 have already said, the species are very difficult 

 to distinguish except by examining the male armature. 



General Suminarij of (Jliaraclers. — 



f 1. Cieueriil form long and rather parallel-sided. 



2, Thorax not more than twice as broad as long ; the sides practi- 

 cally straijrht. 



3. Thoracic stria.' \o\v^ and straight. 

 A.<( 4. Elytra with the black lines usually not spreading into patches ; 



lines not usually broken, 

 o. Prosternum Hat, with a tendency to be slightly concave ; some- 

 what dull in ajipearance, owing to closely-set fine punctura- 

 i^ tion H.mid scattered large i)unctures. 



, I 1. Ant. tarsal claws almost equal in length. 



° ■ j '2. Basal segment of niediau tarsus not excised on posterior side. 

 ^ . 1. Elytra covered with liue puncturatiou. 



With regard to aideagal characters, the figures show all 

 that is necessary. Note the narrow triangular form of the 

 left accessory lobe, with its dorsal edge sliglitly concave and 

 fringed with a row of fine stiff hairs, which row extends to 

 the blunt apex and ends in a small tuft. Edwards wrongly 

 describes and draws this lobe as without the hairs. The 

 side of the tongue .shows a thin cliitinous ])atch slightly 

 creased longitudinally. Possibly this is of similar use to the 

 more elaborate saccular region of the more complex types. 



2. Il.Jluviatiiis, Aubc. 



This species is almost confined to running water, and is, in 

 fact, the most typically " river species " of the " rujicollls" 

 group. It is suj>erfici;dly, perhap.s, the mo.st easily distin- 

 guished species, which, however, is not saying very much. 

 It is fairly widely distributed throughout the Britannic ana, 

 and also on the continent, and, as wc have seen, the female 

 shows variations with regard to the fine ])uncturation of the 

 elytra. The species is recorded from most parts of Ireland 

 and England, but there is, so far, no Welsh record, and it 

 seems to bo absent from Scotland north of Stirling. I failed 



Ann. cC- Maj. 3'. Ilist. Ser. 8. Vol. xv. b 



