Genera Bledius, Heterocerus, and Dyschirius. 35 



Danish species: — I. A. talpa, Gyllb., m. fr. 2. A. stib- 

 terraneus, Er., fr. 



b. Sockets of anterior pair of coxae closed. 



Terminal part of mandibles with two teeth behind the apex. 

 Anterior margin of labrum straight. Teeth of the comb with blunt 

 points. 



Hesperophilus, Steph. 



Danish species; — 1. H, urenarius, Payk., fr. 



II. 



The manner in which Erichson, in his work * Naturgeschichte 

 der Insekten Deutschlands/ has treated of the numerous 

 small Clavicornia has aiForded a new starting-point for in- 

 vestigations of the often very difficult natural history of these 

 animals. His principal object being to reduce to order the 

 confused mass of material by settling the species, it was but 

 natural that he should be more successful in distinguishing and 

 separating than in combining. It is therefore to be expected that 

 future more penetrating investigations of the structure and de- 

 velopment of these Coleoptera, and more strictly scientific com- 

 parisonsj will in some cases result in the principal systematic 

 value being attributed to points now less regarded or overlooked, 

 and in essential changes in his classification. The last four 

 families more particularly, Byrrhii, Georyssii, Parnidae, and 

 Heteroceridffij exhibit so close a relationship in all essential 

 features, especially in the structure of the mouth, and in all 

 stages of tlieir development, that it is more than probable they 

 will have to be regarded merely as subdivisions of one and the 

 same family, each expressing a peculiar modification of the same 

 fundamental type; for it will be found that all those characters 

 which distinguish these families from one another are merely 

 expressive of the different requirements of movement and re- 

 spiration in diff'erent kinds of localities and difi"erent media. In 

 Bi/rrhus we find this Coleopterous type developed for life on 

 land, in shady and moist places, and for feeding on moss. In 

 other genera we find an incipient modification calculated for 

 wetter localities. Still within the pale of Byrrhi we meet with 

 Limnichius, living on the shore itself, and Syncahjpta, which is 

 enabled, by club-shaped bristles on the back, to carry about a 

 protecting shield of mud. In Georyssus^ we see the same type 



* With regard to the character " presternum membraneum," on which 

 Erichson lays so ranch stress as being peculiar to Georyssus, it must be 

 observed that the prosternum of these Coleoptera is as bard as any other 

 ])art of their skeleton; but it is very narrow, owing to the manner in which 

 the head is retracted, and consists only of a narrow, arched, transverse 

 band, which, besides, on account of its hidden position, does not acquire 



3* 



