ORDER I. COLEOPTERA. 69 



such by their hind legs, which are long, somewhat flat- 

 tened, tapering, and fringed with hairs ; and occasionally 

 present more remarkable modifications of form (see 

 Gyrinus, p. 86, figs. 11, 12), and are obviously fitted for 

 swimming rather than for walking. 



The large Dyticus, a beetle common in fresh-water 

 aquaria, is an example of this division, and it, and the 

 smaller and commoner Acilius (PL I., fig. 3), much 

 resembling it, and which may be seen floating tail 

 upwards, in almost any pool or duck-pond in the country, 

 are both well-known insects. They are rendered con- 

 spicuous by the curious fore-legs of the male, three of 

 the tarsal joints of which are spread out, and together 

 form a nearly circular disc fringed with strong hairs 

 and studded with suckers, forming a singular and beauti- 

 ful prehensile organ. 



In the Dyticus, as in the other predaceous water - 

 beetles, the long oar-like hind-legs are conspicuous and 

 well-marked as natatory organs ; and, like most other 

 rapacious animals, the Dyticus is enabled to move very 

 swiftly. This powerful insect, enclosed in plate-armour, 

 swift and ravenous, must be a frightful antagonist to the 

 soft-bodied inhabitants of the waters. 



In the Oxford Museum is one which was taken in the 

 act of devouring a young pike longer than itself. A 

 fierce fight between two Dytici is no uncommon sight, 

 and the male frequently falls a victim to the fury of the 

 female, who attacks and eats him. When however this 

 does not take place, the male usually dies first, and is 

 then devoured by his wife. 



The larva is a slender, active animal, with a pair of 

 long, sharp, and curved jaws (see fig. 26, p. 57), which 

 make it no less formidable a companion than the perfect 

 insect. A writer in the " Zoologist" gives a rather 



