112 MODERN CLASSIFICATION OF INSECTS. 



clibles are short but very robust ; their bodies generally of an oval 

 form ; the hind legs are ciliated, and formed for swimming, or rather 

 paddling, in the majority ; and the tarsi are variable in the structiu'e of 

 their joints. 



Mr. MacLeay divides this stirps into the five following families : — 



Normal group ? J" Heteroceridfe ? 



Palpi shorter than the antenna?. |_ Parnida?. Analogous to the Gyrlnlda3. 



Aberrant group ? f Helophoridm. 



Palpi at least as long as tlie an- < Hydrophilid;e. Analogous to the Dyticids. 

 tenna?. (^ Sphajridiidaj ? 



To these Mr. Stephens has added two others, viz. — 



Limniida? (subsequently described as portion of the family Parnida). 

 Anisotomidie ( Agathidiidte JFestw.), 



but until these various groups be strictly analysed, and entomologists 

 made acquainted with their larvte, the distribution and arrangement 

 of the families cannot be considered as fixed. The Hydrophilidte, 

 however, appear to be the typical family ; although, in their strict 

 natatorial habits, general appearance, and, more particularly, in the 

 circumstance that some of the true Hydrophili recede from the Ry- 

 pophagous habits of the family, and feed in the larva state, according 

 to M. Illiger, upon aquatic mollusca and larva;, it is evident that they 

 approach more nearly towards the predaceous Dyticidae, although, 

 when arrived at the perfect state, they become more perfectly herbi- 

 vorous, whilst the Heterocerida;, Anisotomidae, and Sphaeridiidaj evi- 

 dently conduct us towards other groups. 



In the Regne Animal we find these insects far removed from the 

 Dyticidae*, and employed to establish a passage between the Clavi- 

 corn and Lamellicorn Beetles, in the following arrangement : — 



c jet' c r^^ • f Tribe 1. Hetcrocerus. 



toecond Section ot Llavicornes. J r *r, o 



I Tribe 2. -' P=i'""M^' ^'^; 



I **Elniis (Limnius), &c. 



Jrp ., , r *Helophorus, &c. 

 ^ ...^,,^„. ..^^. . ■ \_ **Hydrophilus, &c. 



(_ Tribe 2. Sphjeridium. 



I have, however, preferred following in the steps of MacLeay and 

 Stephens, by introducing the Philliydrida between the Hydradephaga 



* In the Families Naturelles, we find the following note, relative to the affinities 

 of these insects : — " Les palpicornes conduisent par un bout aux macrodactyles 

 (Elmis, &c.), et par I'autre aux spheridies, aux bousiers, &c. Les Dryops, genre de 

 la tribu des macrodactyles, semblent se lier avec les gyrins de ceux-ci on passe aux 

 Dytiques et de-hi aux carabirjues. " (P. 36'5.) In the Rcpie Animal (vol. i, p, 519.) 

 we also find various observations in support of the nearer relation of the Ilydropliilida; 

 to the Necrophaga and the I/amelllcorns, than to the Dyticida?. 



