March, 1 9-' I.] BlATCHLKY : XoTES ON l.NDIANA HaI.TICINI. 1, 



without name by Horn, loc. cit.. p. 207,, as occurrinir in l-'lorida and 

 Louisiana, thouj^h lie does not refer to the most salient differences 

 between it and f>cnnsxl7'a}iica. 



The small Halticids belonfjinj:; to the j^cnus Loii(/itarsus are much 

 more numerous in this country than is pfenerally supposed. I have 

 elsewhere described three very distinct forms from Florida which 

 were not included in Morns paper, and have at hand four others 

 which have been lieretofore unknown. They frequent, for the most 

 part, the dense subaquatic vegetation along the borders of marshes 

 and ponds, where their small size precludes their being easily seen. 

 They are best taken by sweeping, but this method of capture usually 

 prevents their food plant being definitely known unless, as is seldom 

 the case, the vegetation is of a single species. 



The study of this genus, while a most interesting pastime, is beset 

 with many difficulties. Crotch passed it up with the statement- that : 

 " The species are beyond my skill to unravel from the incomplete 

 material before me." Horn, loc. cit., p. 276, stated that: "The genus 

 is an extremely difficult one to deal with, certainly more so tlian any 

 other Halticini of our fauna," yet he made a very satisfactory key to 

 2^ species from all parts of the country, 15 of which he described 

 as new. 



Our eastern species of Longitorsus group themselves naturally 

 into two divisions, one having the wings present, the elytra wider at 

 base than thorax and with umbones and humeri distinct; the other 

 apterous, the elytra not wider at base than thorax, the humeri, at the 

 most, broadly rounded and the umbones absent or very faint. These 

 groups should at least bear subgeneric rank. In order that our 

 ea.stern species may be the more readily determined I have prepared 

 the accompanying key to the 19 now known from ea.st of the Missis- 

 sippi River. In my study of both these and other small Coleoptera I 

 have found that the presence or absence of an alutaceous surface is 

 one of the most stable characters to be used in separating clo.scly 

 related species. This and the color, which varies but little in mature 

 specimens of Lougitarsus. and the length, which can also he de- 

 pended upon within the limits given, arc the |)rincii)al second.iry 

 characters I have used in the kev. 



2 Proc. .\cafl. N.it. Sci. Pliil., 1S73, 65. 



