122 MODERN CLASSIFICATION OF INSECTS. 



found, in company with the perfect insects, in the autumn. The former 

 are anopluriform, measuring, when full grown, about two and a half 

 lines in length, and half a line in breadth ; they are of a uniform black 

 colour, and have the apex of each abdominal segment fringed with 

 very short hairs ; their food is probably mucor, and they prefer rough 

 slimy stones. When full grown, they leave the water, and construct, 

 upon the edges of the stone, a small cell, by agglutinating together 

 small particles of mud. These cells are sometimes very numerous, 

 giving the fragment of stone a curious appearance. The pupa is of 

 an orange colour ; and the imago, when hatched, gnaws its May through 

 its prison. This account will be observed to correspond with that 

 given above relative to the nests of Elmis. 



Relative to the British genera, few particulars will suffice. The 

 large size of the eyes in Hydrochus, the shortness and slenderness of 

 the terminal joint of the maxillary palpi in Octhebius, and the extra- 

 ordinary elongation of the same organs in HydriEna, are interesting 

 peculiarities. One of the species of the last-named genus is found 

 in brackish water ; and Mr. Haworth [Ent. Trans, i. p. 87.) states its 

 habitat to be " ad littora salina," near Kingston upon Hull. 



The genus Spercheus has been arranged by Leach and others with 

 the Hydrophilidse. It, however, appears to be the connecting link 

 between the two families, approaching nearest to the Helophoridge in 

 the structure of the legs, habits, and oral apparatus. The cui'ious 

 structure of the maxillae {Jig. 8. 4.) induced Fabricius to place it be- 

 tween the beetles having six and four palpi to the maxillae. 



The fourth family HYDROPHiLiDiE * is distinguished by the ovate 

 or hemispherical and convex form of the body, which is not contractile 



* BiBLioGR. References to the Hydrophilid^. 



Leach, in Zool. Misc. vol. iii. 



Solier, in Ann. Soc. Ent. de France, 1 834. 



Audouin and Brulle. Hist. Nat. Ins. Col. vol. v. 



niiger. Kaf. Pr, and Mag. vol. i. 



Germar. Ins. Nov. Sp. 



Say, in Journ. Acad. Sc. Nat. Philadelphia, vol. iii. 



MacLeay. Ann. Jav. 



