ll^ MODERN CLASSIFICATION OF INSECTS. 



legs broad, compressed, and serrated i^fig. 7. 3.) ; the thorax much nar- 

 rower than the elytra, especially at its hinder part ; the jaws robust, 

 toothed, and advanced (^^. 7- 4.) ; the antennae {^fig. 7. 2.) short, with 

 the two basal joints large, and the remainder forming an elongated club ; 

 the palpi very short ; the tarsi are short, and 5-jointed, the basal joint 

 (overlooked by Curtis and MacLeay) being minute and oblique ; this 

 part of the leg is capable of being folded back upon the tibiae when the 

 insect is engaged in making its burrows, which are formed, by the assist- 

 ance of the broad flat spinose tibiae, in the mud of the banks of ponds 

 or stagnant water, out of which the insects make their escape when the 

 earth is shaken or stamped upon, and again as quickly burying them- 

 selves in the mud. It is in similar situations that the larva was dis- 

 covered by Miger* ; I am not, however, aware that any description 

 has been hitherto published of it. Mr. Ingpen has communicated to 

 me a larva, several of which he found upon damp mud, in situations 

 where he had taken Heterocerus marginatus', and of which I have 

 given an outline i^fig- 7. 5.) : the head is broad ; the eyes small, and 

 placed behind the mandibles, which are strong, bent, and toothed at 

 the tip ; the three thoracic segments are large, and wider than the 

 head, and the nine abdominal segments are much narrower, and sub- 

 cylindric ; the legs are strong, and armed with a robust hook {^fig. 7. G.) ; 

 the body is clothed with long hairs. The situation in which these 

 larvae were found, and their general structure, lead me to regard them 

 as those of Heterocerus marginatus. 



From the advanced structure of the head of the imago, and the 

 strength of the trophi, it is supposed that the habits of these insects 

 must be carnivorous ; and Mr. Curtis mentions that one of the species 

 was met with under small dead crabs, left by the tide, beneath which 

 they were burrowing into the sand. The bodies of these insects are 

 clothed with a fine silky pubescence, whereby the action of the water 

 upon their various parts is prevented. They walk but slowly; in the 

 hot sunshine, however, I have observed them raise their wings, fly 

 off, and again alight, with all the agility of the tiger-beetles. Their 

 mode of walking is rather peculiar ; the anterior parts of the body 

 being considerably elevated. Mr. Curtis notices the variations of 

 breadth of the thorax, as probably indicating sexual distinctions. We 

 are indebted to M. Leon Dufour for an admirable memoir on the ex- 



* Kirby and Spence [Introd. vol. ii. p. 294.) introduce Heterocerus in a list of 

 Coleopterous genera having aquatic larvae. I know not upon what authority. 



