130 BKTTISH KNTOMOSTUACA. 



which is quite transparent, a good deal of resemblance 

 to a harp. Beak rounded and obtuse. 



Eye areolar ; accompanying black spot nearly half the 

 size of the eye, and rather square-shaped. 



Superior antennae of considerable length, the termina- 

 ting seta3 being much longer than in the other genera. 

 Inferior antennse or rami slender, and of considerable 

 length, each branch provided Avith three long setae from 

 the extremity of last articulation only. 



The rami and setae together extend almost the length 

 of the shell, reaching nearly to its inferior extremity. 



The upper part of the l)ody of the animal is very 

 rounded, and crenated on the outer edge. 



Abdomen slender, not serrated on under margin, but 

 marked near the edo-e with a row of indentations, and 

 terminating in two claws, which are long and slender. 



First pair of feet large. 



Intestine convoluted, having one turn, and nearly half 

 another. 



Hub. — Pond in Osterly Park ; ditch near Richmond ; 

 pond on Bowmont Water, Yetholm, Roxburghshire ; 

 Dunglass Pond, East Lothian. Summer months. 



2. AcROPERUs NANUS. Tab. XVI, fig. 6. 



AcROPEfius NANUS, Baird, Ann. and Mag. Nat. Hist., ii, 93, t. 3, f. 8, 

 1843 ; Trans. Berw. Nat. Club, ii, 151. 



Somewhat resembles the last in shape, but is very 

 small, not the seventh part the size ; is less transparent, 

 less deeply sinuated on anterior margin, and less pro- 

 jecting at lower extremity. 



The strise or ribs are riot so large, and are disposed 

 in a waved form, obliquely transverse ; anterior margin 

 ciliated. 



Beak rather long, sharper than in the preceding species. 



Inferior antennae or rami slender, and rather shorter 



