Till-: \AL\V BKK.TMOS. lOD!) 



Tlicy li.-iv tile held proiiiiiiciil. soiiicw li;i( luin-dwcd behind the 

 eyes ; anlciitia' fill Ion n. sh'iidci-. ;il h'.-isl lialf as hmu' as body ; 1 hoi-ax 

 (inadratc without side iiKii'f;iiis. not wich'i- than head. Elytra widef 

 tlian thorax, dc^prc^ssed, eylindrieai or somewhat ti"ian.uular, \isnally 

 nari'owed lowai'd the lips, and e;ich marked with ten I'ows of (piad- 

 i-ato, rarc^ly roniuled, punctui-es. In eoh))- 1he> are iisuall,\- more 

 or less luctaliie, ol" a tirecMiisii, bronze or |)nrplish hne. The under 

 side is [)aler and densely elothed with a line silky pubeseenee, which 

 (^nal)les them to sIumI the water when the plants np(»n which 1he>' 

 aliii'ht happiMi to be suhmerii'ed 



'I'he pi-inci[tal papers treating' ol' the ti'ibe are as follows: 



LcContc. — "Synopsis of the Species of DoitacUi Iuhabitin<^ the 

 United States," in Proc. Phil. Aead. Nat. Sei., V, 1851, 

 310-316. 



LoKj, ^'^a^•.--"l\e^'ie\v of the T)(>)i(ici(t of P)oreal America," in 

 Trans. Amer. Kn\. S(.c.. XVIH. 1S!)1, iriO-lTC 



The tribe comprises but two ucnera, both of which are repi-e- 

 sented in Indiana. 



KEY TO GENEISA OK l)0\A( IIM. 



a. Elytra siiuiilo at tiii: tarsi dilated, spi'iiu'v lieucatli 1. lJn.\A( i.\. 



(/(/. Elytra distinctly spinese at tiiK tarsi iiari'dw. suinnlji lieiiealli, last joint 



very lonj;. claws large. II. II.kmonia. 



I. DoN.ujiA Fab. 1775. (Gi-., "a reed.") 



Belonging' to this genus, as characterized al)ove, Leng. in his 

 latest s.yno]isis, recognized 20 spiM-ies and a number of varieties. 

 Eighteen species have b.een taken in Indiana, \vhile fonr others may 

 occur. 



In those species having the "sntural margin sinuate ])ehind the 

 middle," there is an apparent second margin, starting not more 

 than one-fourth the length from the tip— often less — which is sinu- 

 ate, or curved more or less, away from the suture. Thus a space 

 somewhat elli])tical in shape is formed, sometimes depr(^ssed, some- 

 times in the same plane* with the rest of the elytron, and alwa\'s 

 destitute of [)!nictuation. 



The mah^s ar(» narrower than the females and usually have the 

 hind femora moi'(> strongly toothed and the last dorsal segment 

 shorter and either truncate or emarginate, never rounded. Last 

 dorsal of female more or less elongate, always rounded. For con- 

 venience the Indiana sjx'cies are separated into three grouj)s and 

 these in turn into species. 



