BEETLES OF THE DISTRICT OF COLUMBIA— ULK'E. 



39 



ECOLOGICAL NOTES— (Vmtinnod. 



Cmtacanfhu^<h(hi>t.<, one of our iiio^t com- 

 mon Carabids. 

 A(ion(>der(i><. All species of this genus are 

 common, except indisthicfuf^, te><tiiceu.'<, 

 and micros. 

 Discodcrm iniehrn.voi, very rare. 

 Gynandropiix liylaris, very conunon. 

 liarpahis ciilii/inosiis, extremely abundant, 

 especially at electric lights in midsum- 

 mer; all the other species are more or 

 less common everywhere. 

 Sdenophorus pedicuhirlus. This and the 

 other species are common; especially 

 at electric lights. 

 Steiiolophus, common on wet places, except 

 ahernam, which is very rare on mud 

 banks near the Potomac. 

 Acup(dpHx, like Stenolophus. 

 Brndiiirlliis l!riearis, many specimens of 

 this lare si)ecies found near swampy 

 places in spring; the other species are 

 common in moist grounds. 

 Tdch iiceUus, common, like Ste)iolophn8. 

 Aiiisodadylus discoidem and baltlmorevsis, 

 abundant along the rivers and at elec- 

 tric lights; laius rather rare; the re- 

 maining species are connnon every- 

 where. 

 XeMonotKS lu{/nl>rix, not common, along 



the river. 

 Aiitphmla inter.«iill<di.% very common. 

 Aiii)<ot.arsusten)iiii(ihi.%('on\m>m; )iiiidipni- 



iris, less common. 

 Spovgopus vertically, rare. 



HALIPLID^. 



Haliplm Iriopsis, common in ponds of 

 stagnant water; pundaius, rare; ruficol- 

 lis, one specimen found. 



Cnemidotiis i^mph'j- and IJ pnnclatus, in 

 pools of stagnant water. 



DYTISCID.E. 



Canthydrus and Hydrucalhvs. abundant in 



stagnant water. 

 Laccophilui<, common in pools and Howing 



water. 

 Hydrovatus and Dt'sinapaclirid, aliumh^nt 



in stagnant water. 

 Bidessiis, common, excejit jl<irictidi>i and 



granarius. 



('cli)i(i (iiKjiislata, very connnon m juiols 



on tlie Potomac Flats. 

 Caiandim rrubihis, common, dissimiUs, one 



specimen. 

 Hydroporux, all the si)ecies are more or 

 less common in brooks and creeks; 

 ohlitus, in cold springs. 

 Ilyhius higvttulns, very common, esjieciaily 



at the electric lights. 

 Coptoiomus and Cdjirlntus, abundant. 

 Mntv.t hicarinah(-'<, not connnon. 

 AgahetcK acuduclits, rare. 

 Agcdms crythropteruH, rare in springs; the 



rest more or less common. 

 Rlnmim calidvx, two specimens at electric 



light. 

 Hydadcm hiin<irgiv(ii<i-% few specimens at 



electric light. 

 DyliscKs hybridxis, rare. 

 Aciliiis rnedioius, not rare. 

 TlicniiO)iedc>< hdnilaris, very abundant, 

 especially at electric lights; onutlicoUis, 

 rare. 

 Graphoderus lihcrux, rare. 

 CyhisterfimbriobdKx, common in i)onds. 



GYRINID.E. 



Divciitrx, more or less abundant in schools 



in stagnant and running waters. 

 (; Ill-ill U.S. Hke Dineutes. 

 nrluiiliiirii.s lineatus, in pools, common; 



iiiijidnalas, less common. 

 Ilydrochm submpreus, very abundant in 

 pools; sc.abralnsand inu'qmdis, not com- 

 mon. 

 Ilydrnixi pennsylranica, extremely al>nn- 



dant. 

 HydrophUm Irimiguhirix, very al)un(lant 

 at electric lights; also <,ntln,, but less 

 abundant. 

 Tropisternus and llydrocliarix, common at 



electric lights. 

 BeroKiix peregrinn.'i and xtriah(><, very com- 

 mon; c.ilginis, rare. 

 Larcoliinx ayilis, extremely abundant 



everywhere. 

 Philhydrus, all connnon, except jirrplcrns. 

 Helochares iu(icnH<'oIlix, connnon. 

 Ilelocombus bijidns, rare. 

 Cyudiiodyki _tiriibri<il't. not rare; blauchardi, 

 rare. 



