HISTORY OF INSECTS. 19 



antennae, inserted in the front of the head, rather 

 towards each side : each of these is composed of 

 two joints, the first, or basal joint, stout, the 

 second, or apical one, divided into many rays, 

 which fold back on the first joint : it has two very 

 small eyes on each side of the head. 



52. The body of the larva is divided into twelve 

 segments besides the head ; of these, the second 

 is incrassated, and furnished below with a retrac- 

 tile 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. 



53. 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 prehensile foot, and 

 remains a long time perfectly still and immov- 

 able. 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 during the 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. 



54. The food of the larva is unknown : when 



c 2 



