272 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XV. 



delicate and are either at right angles with their segments or pass back- 

 wards parallel with the body. They have their origin at the posterior 

 angle of the segment. Besides the above, on the 5th to 10th segments, 

 at their posterior angles, are arranged radiate tufts of hairs difficult to 

 discriminate under such a low power and which probably serve as floats 

 (fig. 3) to support the body on the surface of the water. 



[These floats have a different structure to the other bundles of hairs. Each float 

 consists of a peduncle bearing a radiate series of acuminate flattened scales (see 

 Fig. 3).— E. E.G.] 



The breathing tubes, two in number and reddish in colour, lie parallel 

 with each other and pass backwards over the last segment but not 

 beyond its anterior third ; they arise from the eighth segment from 

 somewhat enlarged dark green bases. 



The ninth segment (fig. 4) is pointed posteriorly and carries three 

 bundles of hair, the central one directed backwards and half the length 

 of the external ones which pass outwards and backwards. Beneath them 

 is a somewhat thick bundle of hair by which the insect is enabled to 

 attach itself. 



The larvae under a lens of f" focus may be thus distinguished at 

 various stages of growth. 



Larva 1 mm. Head light red, mottled with darker red, sometimes 

 dark brown, base of head dark red. Antenna; brown eyes not distin~ 

 guishable • thorax smaller than head, anterior third white, posterior 

 two-thirds olive green and body olive green. 



Larva 2 mm. Head reddish mottled with darker brown, thorax not 

 broader than the head, anterior portion white, usually forming a white 

 collar at the junction of the head with the thorax, remainder of thorax 

 dark olive green, body the same with darker central line, penultimate 

 segment paler, breathing tubes brown ; the branching setae on the 

 various segments quite distinguishable. 



Larva 3-4 mm. Head dark reddish brown mottled with lighter 

 brown, thorax broader than head ; collar less conspicuous, particularly 

 so in middle lino, but very variable ; very frequently the collar is 

 replaced by two conspicuous white dots on either aide of the middle 

 line, occasionally with a brick red spot between them. In other speci- 

 mens the spots are translucent green, almost the same colour as the rest 

 of the thorax. 



Larvae kept in a vessel of clear water with a sheet of white paper 

 beneath, are altogether paler in colour than above and may even be 



