776 THE POPULAR SCIENCE MONTHLY. 



A relative of the dragon-flies, the ant-lion, when in the larval state, 

 digs a conical pitfall, at the bottom of which it lies buried, with only- 

 its strong jaws projecting. Here it patiently waits for an ant or some 

 small creature to tumble in. If the struggling animal seems libely to 

 clamber out, the ant-lion hurls sand at it to bring it within reach of 

 the fatal jaws, where it is surely lost. 



Ants sometimes undertake the dairy business. Being exceedingly 

 fond of a milky fluid which exudes from two tubes situated on the 

 hinder part of the bodies of certain plant-lice, called aphides, to pro- 

 cure it they resort to measures strangely intelligent for even the pro- 

 verbially wise ant. They have been known to build mud stables in 

 which the aphides were kept as stalled milch-cows. To cause the flow 

 of milk, the ants irritate or rub the tubes with their antennae. 



Fig. 6.— Ant milking an Aphis. 



With few exceptions fishes depend upon their numerous teeth for 

 seizing food. The sturgeon is toothless, and draws in its food by suc- 

 tion. A single long tooth is used by the hag-fish to transfix its victim, 

 while it bores the flesh with a long, spiny tongue. The angler lies half 

 concealed by sand and weeds, with its enormous mouth agape ready to 

 seize any small fish which may incautiously venture near. Upon its 

 nose is a long, flexible spine, with shiny tip, which, waving in the 

 water, decoys small fry to their death. 



King of fishes, by virtue both of size and ferocity, is the rapacious 

 shark. This terror of the sea has its mouth armed with hundreds of 

 teeth, triangular in outline and serrated on the edges. There are sev- 

 eral rows, and, as the outer old teeth drop away, others rise into position 

 to take their places. 



In Japan is found a beautiful fish which has a sort of gun for bring- 

 ing down insects. It does not have to wait, like other fishes, for the 

 fly to fall into the water by accident. Seeing one lighted near the 

 water, the choetodon gently approaches, and, aiming its beak, blows a 

 drop of water with unerring aim, knocks the unsuspecting fly off its 

 perch into the stream, and devours it, doubtless with a relish begotten 



