56 Proceedings of the Royal Irish Academy. 



Bidrihidion. — Great Britain (common, south of England to Inverness- 

 shire). Central and southern Europe. Denmark (Horsens ; Svejbaek, 

 Petersen). 



Caenis dimidiata Steph. 

 Leinster. 



L. — Westmeath (Shannon ; Coosan Point; Killinure). 



Distribution. — Great Britain. Widespread throughout Europe (Finland, 



fide Aro ; Denmark, fAe Petersen). 



Caenis halterata (Fab.) (C. macrura Steph.) 



CONNAUGHT. LEINSTEB, 



C. — Mayo (Westport Mall). L. — Dublin (Glasnevin, common, Haliday 

 MS.). "Westmeath (Coosan Point; Killinure). 



Recorded in Haliday's MS. list under the name of Caenis macrura Steph. 



Distribution. — Great Britain (not ascertained). On the Continent this 

 species ranges from Lapland to Algeria (Biskra and neighbourhood, fi^ 

 Eaicn, in litt.). 



Baetis binoculatns (L.). 



MCNSTER. CONNADGHT. LeINSTER. ULSTER. 



M. — Kerry (Ross Castle ; Deenagh River ; Woodlawn ; Tore Cascade ; 

 Gap of Dunloe). C. — Mayo (Clare Island). L. — Wicklow (Enniskerry). 

 TJ. — Armagh (Mullinure). 



Distribution. — Great Britain (not ascertained). Widespread in Europe 

 (Finland, .4ro; Norway, Schoyen ; Denmark, Pc<<T«cn, &c.) North America 

 (Hudson's Bay Territory, Eaton). 



Baetis scambas Eton. 

 Leinster. 



L. — Dublin (Lucan). 



Distribution. — Great Britain (occurs as far north as Inverness). Range 

 abroad not known ; has been recorded from Denmark (Horsens ; Skellerup, 

 fide Petersen). Germany (Jiis). 



Baetis vemus Curt. 



Musster. Leinster. Ulster. 



K. — Kerry (Deenagh River ; Tore Cascade ; Horse's Glen; Coppagh Glen ; 

 Gap of Dunloe}. L. — Dublin (Rathfamham). U. — Antrim (Cave Hill, 

 Holiday collection). 



DistriinUion. — Great Britain (uncertain). Finland [Aro). Arctic Norway 

 (Hatfjelddalen,/«fe<S<ra7u£). Germany {Ris). 



