ROLAND HAYWARD, 33 



excellent summary of these earlier attempts at the subdivision of the 

 genus the student is referred to Duval's " De Bembidiis Europreis" 

 (Ann. Soc. Ent. France, 1851, ser. 2, ix, pp. 455-461). Duval, 

 himself, has gone to the other extreme, including in Bembidlam both 

 Tachypus and Tachys. 



In one of his earlier papers (Ann. Lye. N. Y., 1848, iv, p. 451) 

 Dr. LeConte has subdivided the North American species of the genus 

 into four genera, which later, however, he has suppressed, referring 

 all our species to Bembidium. The genera above referred to are : 

 Bembidium, including punctatostriatum, carinula, littorale and irue- 

 qiiale — Odontium, containing coxendix and eonfusum — Hydrium, 

 erected for the reception of Icevigatum — Ochthedromus, including all 

 our other species. 



The last genus to follow in the footsteps of the others was Ameri- 

 zus Chaud., which was based upon tlie peculiar structure of the 

 maxillie, the outer lobe of which is composed of but a single piece, 

 resembling in this respect Callidus.^ The fusion of the two joints, 

 however, is by no means as complete as in the latter genus, the suture 

 between them being visible on the under side. Amerizus was founded 

 on our B. spectablle, and one other species, B. oblongulum, should 

 be referred to it, as pointed out by Dr Horn (Trans. Am. Ent. Soc, 

 ix, 1881-82, p 134), were the genus allowed to stand. It has, how- 

 ever, been united with Bembidium by that author (loc. cit.), and it 

 seems to me better to pursue this course, at any rate for the present, 

 and to regard the two species composing it as aberrant members of 

 the latter genus. 



As may be inferred from what has been already said, no attempt 

 at generic subdivision has been made in this paper, first on account 

 of the poor success that has attended similar efibrts by writers more 

 experienced than myself in systematic work, and secondly because I 

 am familiar with only our North American species. It would un- 

 doubtedly be a great convenience were some good, constant charac- 

 ters discovered for the division of the genus into two or more genera. 

 In oi'der, however, for one to attempt this, if indeed it be possible to 

 do it at all, and to have the results of his work really of service, it 

 seems to me that he must be familiar with the species from all parts 

 of the world where the genus occurs, and not only with those from 

 one region. Bembidium, therefore, as treated in this work, is the 



* For figures of tlie mouth-parts of Ainerisn.i and several Bembidia see Horn. 

 Trans. Am. But. Soc, ix, pi. vi, figs. 36-38. 



TEANS. AM. ENT. SOC. XXIV. (5) FEBRUARY, 1897. 



