464 



THE WIIIELWIG BEETLES. 



air, as it carries a tolerable supply beneath the elytra When, however, that supply is 

 exhausted, the beetle rises to the surface, just pushes the ends of the elytra out of the 

 water, takes in a fresh supply of air and again seeks its subaquatic haunts. Any one may 

 see in almost any ditch the Great Water Beetle (Dyticus marginalis), ever and anon rising 

 to the surface, poking its tail out of the water, and then diving to the bed of the stream. 

 Towards evening, this, in common with many other Water Beetles, is accustomed to 

 leave the streams, to spread its wide wings and to soar into the air. In the early morning 

 it again seeks its watery home, and is accustomed to save time and exertion by closing its 

 wings and dropping like a stone as soon as it perceives the water below. Sometimes, 

 however, it is direfully disappointed, mistaking the glitter of glass, such as the sashes of 



cucumber frames, the tops of 

 green-houses, and similar objects, 

 for the water into which it is ac- 

 customed to plunge, and in con- 

 sequence receiving no small shock 

 when it comes in contact with the 

 hard glass. Even when kept in 

 an aquarium, the Water Beetles 

 are apt to act in this manner, and 

 to leave their residence after dark. 

 The larva of the Dyticus is a ter- 

 ribly ferocious creature, both in 

 aspect and character. It inhabits 

 the waters, and is a very hyfena in 

 the terrible grasp and power of 

 its jaws. The* perfect insect is 

 quite as voracious, and when a 

 number are kept in a single vessel, 

 they are sure to attack and kill 

 each other. No one who cares 

 for the animated inhabitants of 

 his aquarium should permit a 

 Dyticus to be placed among them, 

 as a fox makes no more havoc 

 in a chicken roost than a Dyticus 

 in an aquarium. 



The courage and ferocity of the creature are so great that it will attack insects much 

 larger than itself, and not even the fish can escape the jaws of this insatiable devourer. 

 Before the character of the Dyticus was as generally known as is now the case, a gentleman 

 had put a pair of these Beetles into a vessel of water, thinking that they would be sure to 

 agree and permit him to watch their habits. Next morning, however, when he came to 

 inspect his proteges, he was shocked and startled to find that the male was dead and 

 already half eaten by his disconsolate widow. 



The male of the Great Water Beetle, in common with other species, is specially notable 

 for the singular development of the fore-legs, the tarsi of which are developed into a most 

 extraordinary apparatus caused by the dilation of the three first joints, which are flattened 

 so as to form a nearly circular disc, covered on its under surface with a multitude of 

 wonderfully constructed suckers, one being very large, another about half its size, and the 

 others very small, and set on pear-shaped footstalks. This structure may be seen on 

 reference to the illustration. This forms a beautiful object for the microscope, but requires 

 some care in its preparation, as the air contained in the suckers refuses to permit the 

 Canada balsam to enter, and unless it be w r holly expelled, a series of unsightly black blots 

 is the result. 



The larger specimen in the engraving is the Dyticus dimidiatus, and the smaller is the 

 llylrius ater, both British species. 



To this group belong the WHIELWIG BEETLES or GYKINID^E. so plentiful on the surface 



WATER BEETLES. 

 llybius at*r. Dyticus dimiilidtuf 



