74 VIEWS OF THE MICROSCOPIC WORLD. 



ascertained. This Larva feeds indiscriminately upon all kinds of aquatic insects 

 which it can master, and is itself the prey of the larger water-beetles. When kept 

 together by themselves, without their appropriate food, they attack and devour 

 one another. If they are confined in separate vessels for a few days and then 

 put together, they soon engage in fierce conflicts, seizing each other with their for- 

 midable jaws whenever a favorable opportunity occurs, and displaying the greatest 

 courage ; the assailant sometimes engaging another of twice its own size. 

 These creatures move very swiftly through the water, occasionally rising to the 

 surface for the purpose of breathing. They sometimes hold their tails above the 

 water to attain the same end, admitting, while in this attitude, fresh portions of 

 air into the respiratory organs by means of the orifices near the lower extremity 

 of the body. As these animals gradually increase in size they become more and 

 more inactive, and are often infested with the Bell-shaped animalcules. If this is 

 the case the animalcules become exceedingly numerous, and when the Larva 

 arrives at maturity, the surface of its body then appears to the naked eye to be 

 covered with a fine down, which is nothing else than a vast collection of Bell- 

 shaped animalcules. 



THE LURCO, OR GLUTTON. This aquatic animal is shown in Fig. 111. It 

 resembles a caterpillar in form, and being transparent to a certain degree, affords 

 an excellent object for the microscope, the internal structure of the creature be- 

 ing clearly discerned under a good light. The Lurco is usually found in collec- 

 tions of water where grass and weeds are lying partially decayed. When the 

 day is bright they rove upon the surface of the water, but cluster together at 

 the bottom in cloudy weather. No difficulty is experienced in preserving them 

 alive for months in vessels of water, where they increase rapidly both in size and 

 numbers, if bountifully supplied with their accustomed food. Pritchard states, 

 that having caught in the month of June a number of specimens, which were 

 nearly one-fifth of an inch in length, he kept them in a vessel holding about three 

 quarts until the month of October ; they had been plentifully provided with 

 monoculi, and by this time had become very numerous, congregating together 

 in masses of considerable size, and some of the larger individuals had grown to 

 the length of three- fifths of an inch. The Lurco is not possessed of feet, but is 

 furnished with small tufts of hair set along its sides. Its mouth is fringed with 

 hairs, and when open has the shape of a pear. The gullet, connecting the mouth 

 with the first stomach, is capable of instantaneously expanding to a great extent : 

 it is never completely closed, and the prey of the Lurco, which it always swallows 

 alive, may frequently be discerned moving about in the first stomach and seek- 

 ing to escape through the mouth. The whole body of the creature is divided 

 into a number of stomachs, separated from each other by a transparent ring of 

 muscles, which expands and contracts to a considerable extent. 



The Lurco is endowed with very strong digestive powers, for its favorite food 

 is monoculi, which are covered with a hard, shelly case. These it swallows entire 

 with great voracity, filling itself to repletion, when it remains torpid like the 



