Deioncctea ilepressus, Fal>.^ and cle<:;an.s, Panzer. 297 



cliaiacters, taken in coiijuiictioii with the thorax-characters, 

 fjeiierally orml>le one to si-parato the mah»3 with comparative 

 ease, and so Far, with one exception, I have always been 

 ahle to tletcrinine the specios on these characters, a subse- 

 quent cxaniiinitiou of the jodeagus confirming my previous 

 iletermination. 



3. The yKJea</us. — In the nortliern species this or^an, 

 viewed from al>ove, has a broad apex, wiiile in the common 

 form it has a pointed one, and until my recent visit to Gallo- 

 way I re;farded this character as definitely proving that we 

 linve two distinct species. On looking throu<^h my additional 

 material from eighteen more lochs, I had no difficulty in 

 separating the males of the two forms on tiie thoracic and 



Apices of ledeajri of specimens of IJ. dfjn-essus (" the northern species ") 

 and U. vleyaus (*' the coniuion sjiecies ''), chosen to show the range 

 of variation. — Figs. 1-9. 1). dv]>rctim« (1, Talliin Tarn ; '2, L. of the 

 Lowes; 3, L. Urr ; 4, L. Uoon ; fj-O, L. Dun^'eon). Figs. 10-18. 

 I), eltffrtnt (10, 11, li. Spey ; 12, 1.'^, Long L. of the Dun>jreon ; 

 14, L. Stroan : 16, L. Aber ; 10, L. Skene ; 17, Broadford liiver, 

 Skye; 18, Moorlinch, N. Soujerset). 



tarsal claw-characters except in one case — Loch Dnngeon> 

 the specimens from ■which I put down as " tmcertain." On 

 examining the redengus of these specimens I found a range of 

 width in the apex from that of typical " northern " specimens 

 to a comparatively narrow and bluntly pointed form {vide 

 figs, ^-i) infra). 



Now I had previously noticed that there was a variation in 



