BLEPHABOCEEIDjE. 151 



constriction. All the segments are very strongly constricted at 

 the base and apex, so as to present the extraordinary appearance of 

 thick rings strung on a central axis. Under each of the seg- 

 mental parts is a single pad-like foofc, locomotion being effected by 

 releasing the fore or hind three and moving slightly to right or 

 left, the remaining three following suit after the first three have 

 attached themselves again. 



The pupa is ovate, strongly convex on the upper side, its lower 

 side being quite flat; it lies quiescent, sticking to the rocks 

 permanently by means of its six pads. " The wings and legs lie 

 folded on the ventral aspect (side), which is covered only by a thin 

 colourless pupal cuiicula. From the prothorax project dorsally a 

 pair of respiratory organs, each composed of a thin double-walled 

 plate, the outer plates of each set being strongly chitinized, and 

 acting as protecting covers for the two delicate membranous inner 

 ones ; (the whole arrangement like a two-leaved book, with board 

 covers) " (Kellogg). " The pupa is formed within the larval skin, 

 but the latter is subsequently cast, so that the pupa is exposed ;. 

 its dorsal region is horny, but the under surface by which it clings 

 firmly to the stones of the rapid brook, is white and scarcely 

 chitinised, and Dewitz considers that the chitinous exudation from 

 this part is used as a means of fastening the pupa to the stones Jr 

 (Dr. Sharp, 1899). 



The emergence of the imago from the pupa is very interesting 

 and has been observed by Comstock and by Kellogg ; the former 

 thus describing it : 



"Each midge on emerging, forced its way out through a 

 transverse rent between the thorax and abdomen. It then 

 worked its body out slowly, and in spite of the swift current held 

 it vertical. The water covering the patch of pupae varied from 

 one-fourth to one-half inch in depth. In the shallow parts the 

 adult had no trouble in working its way to the surface, still clinging 

 to the pupa skin by its very long hind legs. While still anchored 

 by its legs, the midge rests on the surface of the water for one or 

 two seconds and unfolds its wings ; then freeing its legs it takes 

 flight. The adults emerging from the deeper water were swept 

 away by the current before they had a chance to take wing. The 

 time required for a midge to work its way ont of the pupa-skin 

 varied from three to five minutes." 



For information on the life-history of some non-Oriental species 

 the following authors may be consulted : Dewitz (Berlin. Ent. 

 Zeits. xxv, p. 61, 1881), and Brauer (Wien. Entom. Zeit. 1882), 

 on the European Liponeura brevirostris ; and Miiller (Arch. Mus. 

 Kio Jan. iv, p. 47, 1881), on a species of either Paltostoma or 

 Curupira ; Osten Sacken (Berl. Entom. Zeits. xl, p. 148, 1895), 

 also adds interesting notes. 



The perfect insects frequent their breeding grounds, the rocky 

 swift flowing streams of hilly regions, lying flat on the vertical 

 sides of the damp rocks, and occur in greatest abundance on sunny 

 days. Their flight is weak. The male is apparently not predatory ; 



