BY R. J. TILLYAItD. 597 



Having thus filled in the gaps in our knowledge in the life- 

 histories of two species of this interesting genus, it remains to 

 give descriptions of the full-fed larvae, and to indicate their specific 

 differences. 



Description of Nymph of Diphlebia I esto'ides (P\a,te xix., fig-l). 



Total lenyth 33 mm. 



Colour dark brown, somewhat paler on legs ; head and cau- 

 dal gills almost black. Head 4-5 long by 5-6 mm. wide. 

 Eyes black, rounded, widely separated ; postocular lobes well 

 rounded, slightly rough ; just in front and below each eye is 

 a series of six or seven sharp spines, which can be seen pro- 

 jecting from under the front border of the eye. Frontal shelf 

 rS long by 3 mm. wide, prominent. The huge labium, already 

 fully described in my former paper (p. 378, and fig. 2), pro- 

 jects beyond and on each side of the front. Antenna; (fig. 5 

 of former paper) long and slender, 5-7 mm. in the specimen 

 under description. Ocelli pale whitish, quite conspicuous. 

 Thorax: profhoraj:, 1-5 long by 4-5 mm. wide, well de- 

 veloped, lateral lobes spiny, not angulated, their shape being 

 rather bluntly sub-triangular, with the tip rounded off. 

 Meso- and metathorax 5 mm. wide; wing-cases 7 mm. long; 

 hind wing-case 1-2 mm. wide; reaching to end of fifth abdo- 

 minal segment. Legs: femora flat and rather broad, 

 smooth, those of fore and middle legs resting in a horizontal 

 plane, but those of the hind-legs raised into a nearly vertical 

 plane; measurement, fore 5-5, middle 6, hind 9 mm. Tibia' 

 narrow, rounded, smooth; about 6 mm. long on all legs; tarsi 

 short, fore 1 '8, middle 2-6, hind 3-2 mm. Abdomen rather 

 short, 12 mm. ; 4 mm. wide at base, tapering to 2 mm. at 

 segment 10. Each segment has a finely pitted, dorsal surface, 

 but appears rather smooth and shiny ; colour dark brown with 

 no pattern. Caudal Gills: median 10-5, laterals 11-5 

 mm., each. The laterals lie in one plane pressing against the 

 rock, but the median gill is held at a slight slant above them ; 

 when crawling, however, the median gill is often depressed 

 so as to be almost level with the other two. All three gills arc 



