ORDER COLEOPTERA. 251 



crowded, and unite into a mass, almost in the form of a 

 spindle, and a little curved. The head is sunk in the corslet, 

 as far as the eyes, which are large, and divided by a border, 

 so that there appear two above and two below. The labrum 

 is rounded, and very much ciliated in front. The palpi are 

 very small, and the interior of the maxillary is wanting, or 

 a mere abortion in many species, more especially in the 

 largest. The corslet is short and transverse. The elytra are 

 obtuse or truncated at the posterior end, and leave the anus 

 uncovered, which terminates in a point. The two anterior 

 feet are slender, long, folded in double, and almost at a right 

 angle with the body, in a state of contraction, and terminated 

 by a very short and very compressed tarsus, the under part 

 of which is furnished with a fine and thick brush, in the males. 

 The other four are broad, very slender, as it were mem- 

 branous, and the articulations of the tarsi form small leaves, 

 disposed like furbelows. 



The gyrini are in general of small or middle size. They 

 are seen from the first days of spring to the end of autumn, 

 at the surface of dormant waters, and even on those of the 

 sea, often assembled in troops. They appear there, from the 

 effect of the light, like brilliant points, swimming or running 

 with an extreme agility, making turns, circular, obliqvie, and 

 in all directions, from which comes the name of aquatic JJea, 

 and tourniquet, given them by some writers. Sometimes 

 they repose and appear perfectly motionless, but the moment 

 they are approached they escape by swimming, and imme- 

 diately sink under w^ater with the greatest celerity. The 

 last four feet serve them as oars, and the first two for 

 seizing their prey. Placed on the surface of the water the 

 upper part of their body always remains dry, and when they 

 dive, an air-bubble, like a silvery globe, remains attached to 

 their hinder part. If they are seized, a milky liquid oozes 

 from their body, and is spread over it, which produces the 



