THE HYDROMETRA. 403 



sures about half an inch in length, and is of a some- 

 what elongated form, and a bluish-black colour, with 

 the surface, especially on the head and thorax, smooth 

 and shining. The short hemelytra, which do not 

 cover one-third of the abdomen, are of a beautiful 

 bright red colour, with a very narrow brownish 

 membranous border on their hinder margin, and the 

 legs are also bright red. Pretty as this insect is, 

 however, there can be no doubt of his thoroughly 

 predaceous habits, for his anterior thighs are much 

 thickened and furnished with a series of close-set 

 bristle-like teeth on their lower surface, and the 

 tibiae are slightly curved to fit the thighs, and like 

 them, armed with numerous short teeth, the whole 

 forming an apparatus from which any small insect 

 seized by it would have but little chance of escaping. 

 On the margins of water, crawling about slowly 

 upon aquatic plants and the fragments of dead vege- 

 table matter which usually occur in such situations, 

 we may frequently meet with a most singular member 

 of this tribe, the Hydrometra stagnorum. Every part 

 of this insect appears to be elongated almost to the 

 extreme, but this is nowhere so remarkable as in the 

 head, which is as long as the whole thorax, slender 

 and cylindrical, except that it is slightly dilated at 

 the tip and bears a pair of small prominent eyes a 

 little behind its middle. From the tip springs a 

 slender rostrum about as long as the head, composed 

 principally of an elongated second joint, both the first 

 and third joints being comparatively short, and on 

 each side near the tip the long, slender antennae are 

 inserted. The legs are very long and slender, and 

 inserted quite upon the sides of the thorax, an ar- 

 rangement which is met with not only in this, but in 



