The Inhabitants of the Aquarium 289 



Neither size, means of defense nor rapidity 

 of motion protect the selected victim. The 

 beetle fastens itself to a convenient part of 

 the body and, undisturbed by the frenzied 

 efforts to escape, the wild dashes against 

 stones, or the wrigglings on the bottom of 

 pond, river or vessel, he feasts on his living 

 prey, inflicting torture and often wounds, 

 from which even good-sized animals perish. 

 The larva of this beetle is dull gray in color. 

 The head is armed with a pair of powerful 

 mandibles, which serve the larva? as they do 

 the beetle. Six legs are attached to the 

 breast. The body is long, slightly flattened 

 and divided into nine rings. The pupa re- 

 sembles the larva, but shows more of the 

 form and parts of the beetle, which leaves 

 it by bursting the back of its shell. To keep 

 this insect successfully, plenty of food should 

 be provided for it. 



The Small Yellow-bordered Water Beetle 

 (Acilius sulcatus) is about half an inch 

 long and proportionally broad. It resembles 



