46 NEW ZEALAND NEUBOPTEBA. 



The larvae of this insect are very familiar to anglers 

 and are generally called " Black Creepers." They are 

 strictly aquatic in their habits, and dwell under the stones 

 in the beds of rivers and streams, where they are often 

 very abundant. These larvae are found in the streams 

 throughout the entire year, but are most numerous during 

 the late spring. Their food consists chiefly of the larvae 

 of Ephemeridae (May-flies), but they prey on aquatic 

 insects generally, which they capture and devour whilst 

 lurking beneath the stones in the bed of the stream. 



The growth of these larvae is probably very slow, and 

 I should imagine that at least a twelvemonth would be 

 occupied by the insect in reaching its full size ; but, as larvae 

 of all ages are found in the streams during the entire 

 year, it is a difficult matter to ascertain precisely the length 

 of time taken by a single individual in attaining maturity. 

 I have, however, observed that small specimens are 

 commonest in the autumn, winter, and early spring, and 

 have also noticed that very small specimens are of com- 

 paratively rare occurrence. It may thus be fairly assume! 

 that larvae, resulting from eggs deposited by the female 

 insect about December, do not mature, at the earliest, 

 until the following October or November. This is cor- 

 roborated by the fact that we do not find any larvae 

 preparing to undergo their transformation during the 

 winter ; but larvae about to change are very abundant in 

 December and January. 



The full-grown larva of C. diversus measures from 1^ to lb inches in 

 length. The head is broad, nearly round, highly polished, black and 

 extremely hard. It is furnished with the usual mouth organs, which are 

 well developed, the maxillae and mandibles being especially powerful ; the 

 latter are furnished with several teeth. The antennas are three-jointed and 

 very minute. The prothorax is oblong-oval, black, extremely hard, and 

 highly polished on its upper surface. Themeso- and meta-thorax each have 

 a pair of horny dorsal plates. The legs are rather short, moderately stout, 

 and furnished with two-jointed tarsi. The visible segments of the abdomen 

 are nine in number, each of which, except the last, is furnished with a pair 

 of cylindrical pointed processes, fully as long as the segment is wide. These 

 processes spring from the sides of the insect, and are the gills ; but as they 

 have a certain superficial resemblance to legs, the larva is sometimes regarded 

 by the uninitiated as a kind of water centipede. The last segment of the 

 abdomen is destitute of gills, but possesses two appendages projecting back- 

 wards, each of which terminates in a pair of very strong, horny hooks. 

 These hooks are very serviceable to the larva for locomotive purposes, 

 especially when it is engaged in climbing about the rocky bed of a rapid 

 torrent. 



When full grown this larva leaves the water and 

 secretes itself under a large stone, immediately on the 

 edge of the stream. Here it excavates an oval cell in the 



