THE SHORT-WINGED SCAVENGER BEETL] 3. 



421 



XLV. Lathrobium Grav. 1806. (Gr., 1 'hidden + life,") 



Medium or small sized Staphylinids having the prosternum 

 shortened and acute between the front coxae ; front tarsi strongly di- 

 lated and densely clothed beneath with large whitish pads composed 

 of flattened hairs; fourth joint of maxillary palpi conical and 

 pointed or needle-shaped. 



Casey, in his " Revision," has divided the old genus Lathrobium 

 as recognized by LeConte, Horn and other authorities, into 19 

 genera, ten or eleven of which are probably represented in Indiana. 

 His distinguishing characters are, in many instances, of minor im- 

 portance and I prefer to rank his genera as groups or subgenera, 

 thus placing all species under the well-known name of Lathrobium. 

 The following is a modification of the key or table of genera as pro- 

 posed by Casey: 



KEY TO INDIANA GROUPS OR SUBGENERA OF LATHROBIUM. 



(/. Elytra without a fold or raised line on the deflexed portion. 

 h. Neck broad, half, or more than half the width of head. 



c. Hind tarsi longer and more slender, the basal joint much shorter 

 than second, the fifth much shorter than the first four combined. 

 (1. Elytra very short, from one-half to two-thirds the length of 

 thorax, their basal angles obsolete; inner wings wanting; ab- 

 domen rather coarsely and sparsely punctate. 



Group A. Apteralium. 

 dd. Elytra varying in length from a little shorter to decidedly longer 

 than thorax, basal angles distinct ; inner wings present ; abdo- 

 men minutely punctate. Group B. Lathrobium. 

 cc. Hind tarsi shorter and stouter, the first and second joints sub- 

 equal, the first four differing but little among themselves and 

 together often but little longer than fifth ; gular sutures parallel 

 and curved, rather widely separated, nearest together near the 

 middle of the surface behind the mouth. 



Group C. Lathrobioma. 

 1)1). Neck narrow, about one-third as wide as head; gular sutures nearly 

 straight, feebly converging behind, nearest together near the base 

 of the head. Group D. Tetartopeus. 



a a. Elytra with a longitudinal fold or raised line on the deflexed portion, 

 the line parallel with the side margin. 

 e. First joint of hind tarsi equal to or slightly longer than second. 

 f. Four basal joints of hind tarsi subequal ; front tarsi feebly di- 

 lated; gular sutures very widely separated, being separated at 

 base by one-third the width of head; body very small and slen- 

 der, not over 4 mm. in length. Group E. Pseudolathra. 

 ff. First and second joints of hind tarsi each longer than the third or 

 fourth. 



