THE CO-MII-CLAWED BARK BEETLES. 1271 



In addition to the above-mentioned characters, the members of 

 the family have the maxillary palpi 4-jointed and often long an 1 

 much dilated ; head suddenly but moderately narrowed behind the 

 eyes, which are usually large, transverse and emarginate; clypeus 

 not distinct, labrum prominent, mandibles short; antenna 1 long, 

 more or less serrate, 11- jointed, the joints, except three or four of 

 the basal ones, studded with large circular, sparsely placed pits or 

 pores; thorax with the side margins obvious; mesosternum short, 

 the side pieces reaching the coxal cavities; metasternum long; elytra 

 rounded at tips ; abdomen with five or six ventral segments, the 

 third and fourth of which are prolonged backwards and with their 

 hind margins leather-like; middle co.xie with distinct trochantins; 

 hind coxa 3 transverse, not widely separated, the intercoxal process 

 in the Indiana genera being narrow, acute and angulate; tarsi often 

 lobed beneath, the front and middle ones five-jointed, the hind ones 

 4-jointed. 



The name of the family is derived from that of the typical genus 

 Cistela, which is a diminutive of the Greek A'/x/r. a "little box or 

 chest," and probably refers to the form of the insects. The larvas, 

 as far as known, somewhat resemble wire-worms in shape, live in 

 rotten wood and have no special economic importance. 



The principal literature treating of the North American forms 

 is as follows : 



LeConte. : " Synoptic table of the genus Ilymenorus," in New 

 Sp. N. Am. Col., I, 1866, 135. 



Le('on1(. "Synoptic table of species of Mycetoehares, " in 

 Proc. Amer. Phil. Soc., XVIT, 1878, 616-617. 



Casey." Synopsis of the Cistelida? of the IT. S.," in Ann. N. Y. 

 Acad. Sci., VI, 1891, 69-170. 



Casey in his Synopsis recognizes 14 genera as belonging to the 

 family. Of these representatives of seven have been taken in In- 

 diana, while those of another perhaps occur. 



KEY TO INDIANA GENERA OF CISTELID.E. 



(/. Tarsi lobed beneath. 



b. Head in repose resting against the prosternum and cox;e, the former 



strongly slanting downward in front of the COXJTP. I. ALLECULA. 



lib. Head in repose free, the prosternmn longer and less slanting in front 



of eox;e; thorax rounded ;it apex, its hind angles rectangular; body 



oblong and parallel. IT. HYMENORI'S. 



mi. Tarsi not lobed beneath. 



c. Last joint of maxillary palpi elongate, triangular; mandibles dis- 



tinctly notched at apex, their tips acute and subequal; antenn.-e 

 more or less compressed and serrate. III. CISTELA. 



