Observations on some species of Orina. 15 



and form a longitudinal waved ridge ; the spiracle is on 

 the middle of the lateral vertical rib, which terminates 

 below in the lateral flange. Two segments at the anal 

 end appear to be retractile for wielding the terminal 

 sucker. The mouth and leg structures are apparently the 

 same as in 0. vittigera. 



Orina vittigera. — The young larva as soon as it has 

 taken its dark colour is 3 mm. long, and fully 1 mm. wide, 

 head and thorax of equal width, colour black, head 

 and thorax shining, abdomen duller but also shining; there 

 are ribs on the abdominal segments that continue down to 

 the latero-ventral flange (no latero-dorsal or subdorsal 

 flange), and some scattered hairs on the head and sides of 

 the thorax, but dorsally the larva is nearly smooth, hairs 

 being few and very short, and for the most part and as 

 compared with 0. tristis it is smooth and hairless. 



The larva changes its skin three times. When full grown 

 it acquires for the first time a yellow prothorax (in the 

 penultimate skin the thorax is often paler) ; the general 

 colour is a dull indian-ink. Except some very fine 

 striations, the segments are smooth generally, and the whole 

 larva looks and is softish; the body is rounded, with no sub- 

 dorsal flange ; the spiracles are just below the continuous 

 smooth dorso-lateral surface, or plate ; below is a lateral 

 region capable of puckering up into a projection in each 

 segment forming a lateral flange, below which the ventral 

 area terminates in what might be called a flange. The 

 dorsal plates, though smooth and without ribs, etc., do, 

 except in fat larvae, form two ridges by the sinking of a 

 central transverse line. The under surface is pale yellowish- 

 green, or olive-colour. There are a few short hairs on the 

 head and prothorax that require looking for ; length, 9-10 

 mm. ; width, head 1*5, proth. 2*4, body, 4*5 mm. 



Orina tristis, var. smaragdina, laid eggs between July 31st 

 and August 3rd ; six eggs found August 4th. One hatched 

 5th ; two hatched 7th ; others preserved. Egg 2*3 mm. long, 

 *8 mm. wide ; oval, sausage-shaped curvature hardly to be 

 detected, i. e. egg nearly straight. Yellow. Young larva 

 visible in youngest egg ; jaws brown, six dark eye-spots 

 on either side, spiracles dark, and three dark marks on 

 either side (wanting in young larva of 0. vittigera) are 

 visible through the egg-shell, one above and behind spiracle 



