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- Genera Bledius, Heterocerus, and Dyschirius. 35 
Danish species:—l. A. talpa, Gyllb., m. fr. 2. A. sub- 
terraneus, Er., fr. 
b. Sockets of anterior pair of coxe closed. 
Terminal part of mandibles with two teeth behind the apex. 
Anterior margin of /abrum straight. Teeth of the comb with blunt 
points. 
HEsPEROPHILUS, Steph. 
Danish species:—1. H. arenarius, Payk., fr. 
If. 
The manner in which Erichson, in his work ‘ Naturgeschichte 
der Insekten Deutschlands,? has treated of the numerous 
small Clavicornia has afforded 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- 
parisons, 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, Parnide, and 
Heteroceridee, exhibit so close a relationship in all essential 
features, especially in the structure.of the mouth, and in all 
stages of their 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 different kinds of localities and different media. In 
Byrrhus we find this Coleopterous type developed for life on 
and, 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 Syncalypta, 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 “ prosternum membraneum,” on which 
Erichson lays so much stress as being peculiar to Georyssus, it must be 
observed that the prosternum of these Coleoptera is as hard as any other 
part 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, ye not acquire 
