MICROSCOPIC DRAWING AND ENGRAVING. 



transmitted through it. The colour of the head is then a strong 

 Indian yellow, with darker shadings of a bright chesnut. The 

 eyes are a brilliant carmine ; its covering of hairs ' is more sparse 

 than when it arrives at maturity ; its swimmers or paddles are 

 shorter, and its head bears a greater proportion to its body. 



54. The manner in which it deals with its prey, shows extra- 

 ordinary intelligence ; many of the creatures upon which it feeds, 

 being crustaceous, are invested on the head and back with a shell- 

 armour, being unprotected on the belly and lower part of the 

 body ; when they attract the notice of the larva, the latter accom- 

 plishes its object by swimming under its intended victim ; when 

 sufficiently near, turning its head upwards, it seizes its prey, 

 between its jointed antennae, A A, fig. 34 ; having thus secured it, 

 it stabs it in the belly with its sharp mandibles, B B, so as to disable 

 it, it then rises to the surface of the water, and holding its victim 

 above the surface, so as to prevent it from struggling, shakes it, 

 as a dog would a rat. 



Its next operation is to pierce it with a weapon represented at D, 

 which issues from a horny sheath ; this instrument, when not 

 in use, is withdrawn into the sheath. As shown in the figure, it 

 is protruded from the sheath to about three-fourths of its length. 

 This curious weapon consists of a piercer and sucker, the one 

 giving the wound and the other drawing the blood or other juices. 

 When from the nature of the part attacked, this weapon fails of 

 its purpose, the victim is seized between the serrated hooks of a 

 pair of forceps, c c, by which it is torn to pieces, and the juices 

 more easily approached by the sucker, D. 



55. "When supplied with abundant food, this creature arrives at 

 its full growth in three or four months, and is then nearly opaque 

 and covered with hair. When caught and kept several days 

 without food, its ferocity is greatly increased, so that it will 

 attack insects much larger than itself, if supplied to it, and will 

 even devour other individuals of its own species. Its prudence 

 and intelligence, however, are displayed by studiously avoiding 

 those with whom a contest would be dangerous to it, such for 

 example as the water-scorpion. 



The eyes are compound, but of a very peculiar formation, con- 

 sisting of seven oval pupils, arranged like leaves on each side 

 of a stem, as shown at E E ; the entire head and chest are curiously 

 marked with lines and spots. 



There are three pair of legs, the fore legs F F, the hind legs H H, 

 and the middle legs G G ; each leg terminates in a sharp claw. Pro- 

 jecting from each side of the body are seven swimmers or paddles, 

 similar in their position and arrangement, though not in their struc- 

 ture . to those of the larva of the day-fly already described ; they are 

 84 



