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Notice of a curious Aquatic Larva, found in a Water Jug at Twizel, 

 Sth March 1839. By P. J. SELBY, Esq. of Twizel-House. 



In length, it measures about three lines, and is of a peculiar shape, 

 being anteriorly slender, and bulging posteriorly into an oval or flask- 

 shape. The posterior extremity is furnished with a small central sucker, 

 and three lateral fleshy protuberances, which also act as suckers, and by 

 means of which it adheres to the glass or sides of any vessel in which it 

 is placed ; it also possesses two fleshy tubercles or pro-legs on the con- 

 vex surface of the first segment ; and its mode of progression is some- 

 thing similar to that of the geometrical caterpillars, as, when wanting to 

 change its situation, it extends its body to its full length, and then fixes 

 its anterior legs, after which it draws up the hinder part of its body to 

 where they are placed, and securing itself by the suckers, thus advances 

 by alternate movements, each step covering a space nearly the length 

 of the whole body. The head is of a so 4 uare form and large, and the eyes, 

 which are black, are situated towards the margin of the hinder angle. 

 On the forehead, two pellucid bristle-like antenna are visible, and the 

 mouth is furnished with a curious apparatus, the parts of which, however, 

 are too small and delicate to be distinctly made out, without the aid of 

 the microscope. Under a considerable power, these parts exhibit a 

 beautiful and highly-curious conformation ; but are admirably adapted to 

 its mode of life and predacious habits in this its larva state. To convey 

 an accurate idea of these cibarian instruments by verbal description, is 

 almost impossible ; for, to be properly understood, they ought to be seen 

 in action, and under the power of a high magnifier. The following de- 

 scription, however, may serve to give some general notion of their struc- 

 ture and mode of action : On each side of the superior part of the 

 mouth, and below the insertion of the antennae, an instrument (which 

 I take to be one of the palpi), of extraordinary configuration, and which, 

 when fully developed, and the animal is engaged in search of prey, pro- 

 jects to a distance on each side of the head or face : the basal part of this 

 instrument is composed of a large and powerful clavate-shaped joint, the 

 apex of a number of bristles, or rather fine laminae, which diverge or 

 open like a fan ; only, that being bent, they form, when thus expanded, 

 a concave or hollow trap. These vibrissae, except in so far as the 

 whole of the apparatus can bs dpened or shut, or placed in a state of 

 rest over the mouth, possess no vibratory motion, nor do they appear 

 to be furnished with ciliae ; but to produce a current, and bring the ani- 

 malcule upon which the larva feeds within the vortex of this curious and 

 delicate trap, two other members of the mouth, and which I consider to be 

 the mandibles, are constantly engaged in alternately catching at a small 

 projection, which is placed upon the upper part of the large joint of the 

 extended palpus. This catching, or sudden jerk, gives to the delicate 



