THE COMB-CLAWED BARK BEETLES. 127:} 



narrower than female and with four basal joints of front tarsi strongly 

 lobed beneath. Female with three basal joints of front tarsi simple, the 

 fourth strongly lobed. Length 0-10 mm. 



Throughout the State; scarce. June 12 August 11. Occurs on 

 dry twigs and beneath hark. 



A. atra Say, black, shining, tarsi paler, length 7.5 mm., is a. mem- 

 ber of the Alleghanian fauna. 



IT. HYMENORUS Mills. 1851. (Gr., "membrane + margin.") 



Smaller oblong or oval species, having the last joint of maxillary 

 palpi in the form of a right angled triangle with the apex and outer 

 sides subequal in length; lobes of the tarsal joints less developed 

 than in Allecula, the front and middle tarsi never having more than 

 two joints lobed and the hind tarsi with but one. Seven species 

 have been recognized from Indiana, Avhile another may occur. 



KEY TO INDIANA SPECIES OF HYMENORUS. 



(i. Thorax sparsely and usually rather finely punctured; upper surface 



shining. 



h. Third antenna 1 joint of male equal or subequal in length to fourth. 

 c. Elytral stria 1 obsolete toward the apex. 

 <l. Elytra with a large reddish spot each side at bnse; length 4.5 mm. 



HUMERALIS. 



(/*/. Elytra uniform in color throughout. 



c. Femora dark brown, tibiae and tarsi paler; antenna? one-half 



as long as body ; larger, 7-8 mni. 2355. PILOSUS. 



<('. Femora reddish-yellow, tibia. 1 darker; antenna? two-fifths the 



length of body; smaller, 5-0 mm. 2.">5(. NIGER. 



i-c. Elytral stria' distinct to apex; antenna? and legs reddish-brown. 



2857. MKI.SHEIMERI. 



hh. Third antennal joint of male distinctly shorter than fourth. 



/. Antenna 1 fully one-half as long as body, the third joint of male two- 

 thirds the length of fourth : thorax narrower than base of ely- 

 tra, coarsely punctured. 2358. PERFOKATUS. 

 //. Antenna- shorter, about two-fifths the length of body, the third 

 joinl of male but slightly longer than second; thorax at base 

 equal in width to elytra. 2359. OBSCURUS. 

 <KI. Thorax densely and rather coarsely punctured: upper surface less shin- 

 ing. 



//. Antenna' stout, third and fourth joints subequal; eyes large in male, 

 separated by a distance less than one-third their width; piceous- 

 black throughout. 23GO. DISCRETUS. 



</</. Antenna 1 slender, third joint distinctly longer than fourth; eyes 

 smaller, always separated by more than half their width; elytra 

 piceous or dark reddish-brown, the head and thorax usually darker. 



2361. DENSUS. 



