4 HISTORY OF INSECTS. 



of the water, and in that situation are hatched by the warmth 

 of the sun combined with the moisture of the water. The 

 larva, is found on the stems of water-plants {Phellandriimi, 

 &c.), on those portions wliich are always covered by the 

 water : it is long, cylindrical, considerably thickened pos- 

 teriorly, and nearly transparent ; its head is distinctly sepa- 

 rated fi-om the body, and is of an oblong form ; it has four 

 jaws moving horizontally, each bifid at the tip, and two little 

 homs in the usual place of antennse, inserted in the front 

 of the head, rather towards each side ; each of these is com- 

 posed of two joints, the first or basal joint stout, the second 

 or apical one, divided into many rays, wliich fold back on 

 the first joint : there are two veiy small eyes on each side 

 of the head. The body of the larva is divided into twelve 

 segments, besides the head ; of these, the second is incras- 

 sated, and furnished below with a retractile conical foot ; 

 the last segment is very minute, and furnished with two 

 small prehensile feet : the air-tubes, so very plainly seen in 

 other aquatic larvae, are totally wanting ; neither is there the 

 least appearance of spiracles or breathing-holes in the sides. 

 The motion of the larva in the water is tolerably brisk ; 

 but on any object coming in contact with it, it instantly 

 becomes motionless, attaches itself by the anterior prehen- 

 sile foot, and remains for a long time perfectly still and im- 

 movable. When it moves from one place to another, its 

 progression is undulating, somewhat like that of a leech, 

 being performed in this manner: — the anterior foot is firmly 

 attached to some object, then the posterior pair of feet are 

 brought up to it, the back arching up diuing t^ie operation ; 

 the anterior foot then releases its hold ; the body is again 

 elongated, the foot attached further on, and the posterior 

 feet again brought up to it. The food of the larva is un- 

 known : when full grown, it spins a Httle silken sheath, in 

 shape like a watch-pocket, which is attached to the plant 



