MINUTE AQUATIC ANIMALS. 71 



are of a bluish green, and others red, with the receptacles of the eggs of a green 

 color. In the specimen from which the drawing was taken the shell was richly 

 adorned with bright red hues. 



THE VAULTER. The appellation of Vaulter is given to the minute insect 

 which is represented, highly magnified, in figure 105. It derives its name from 

 the circumstance that it transports itself from place to place by successive leaps, 

 in the manner of a flea. As a person approaches, it remains quiet for a short 

 time upon the leaves of the plant on which it happens to be ; but soon springs 

 away to some other place, a motion which it effects by bending its body and 

 darting away from point to point, by the force of the recoil. In England the 

 Vaulter appears in the greatest numbers in the months of April and May, swarm- 

 ing upon the stalks and under side of the leaves of healthy duck-weed, growing 

 on the surface of the water. Stagnant water, filled with decayed plants, is de- 

 structive to them, and in order to preserve them, they must be provided with 

 plenty of clear, pure water. The Vaulter is very active, and when caught, is 

 usually detected in the eager pursuit of its prey. The encasing shell of this 

 creature is similar to that of the Small Water-flea, but differs in having a greater 

 number of parts. The body tapers also more gradually, and the horns do not con- 

 tain so many joints as those of the former. It is also distinguished from this insect 

 by having under the beak a single organ of respiration, whic*h is delineated in 

 figure 106. This instrument is in constant motion, and causes a current of 

 water to set towards the animal, like the cilia of the Infusoria. The legs are ten 

 in number, and are fringed with hairs ; and the tail of the Vaulter, which con- 

 sists of two parts, is ornamented in the same manner. The eye is deeply 

 imbedded within the shell, and its position in the figure is indicated by the let- 

 ter c. The upper part of the Vaulter gleams with a bright red hue of various 

 tints, fading down to salmon color on the under side of the body and legs ; 

 while the tail, the tufts of hair which fringe the legs, and the horns or feelers, 

 are of a bluish green. The Vaulter is only one three-hundredth of an inch in 

 length. 



THE LARVA OF A SMALL BOAT-FLY. This insect is so called from its re- 

 semblance in form to a boat. They swim on their backs, and propel themselves 

 with considerable force by means of their hinder feet, which are shaped like oars. 

 Pritchard observes, that they are found during the spring, playing upon the sur- 

 face of ponds and streams, and immediately seeking the bottom when disturbed. 

 They acquire their full richness of color, and attain their perfect state in the fall 

 months, at which time they deposit their eggs, which are small in size, and con- 

 sist of a jelly-like substance. As the young advance towards maturity, they 

 shed their skins several times ; at which periods they are colorless throughout, 

 except the eyes, which are of a light crimson. 



They acquire their peculiar tints sometime afterwards, the lower part of the 

 body changing through every variety of hue, from a pale yellow to a rich car- 



