THE MELANDRYID BARK BEETLES. 1287 



Horn, in liis latest paper above cited, divides the family into ten 

 tribes. Of these representatives of seven have boon taken in In- 

 diana, while those of two others probably occur. 



KEY TO INDIANA TRIBES OF MKLANDKYID.E. 



a. Next to last joint of all the tarsi simple: Ir.mt tarsi of males not di- 

 lated: thorax as wide at base as elytra. 



h. Antenna' with last three or four joints suddenly larger, forming a 

 1 >(ise, strongly developed club; length less than 6.5 mm. 



Tribe I. TETRATOMIM, p. 12M. 

 &&, Antennae gradually thicker or filiform. 



f. Front eoxal cavities with an outer fissure or cleft. 

 (I. Third joint of antenna.' as long as fourth and fifth together; form 

 broadly oval. Tribe II. PENTHINI, p. 12S9. 



<ld. Third joint of antemue not much longer than fourth; form elon- 

 gate. 



c. Front coxre not prominent, rather widely separated ; species 

 strongly resembling Mfltuiutus; length 10-11 mm. 



Tribe III. SYNCTIRWXI, p. 1290. 



ee. Front coxre moderately prominent and nearly < .ntiguous; color 



piceous ; length G-S.5 mm. Tribe IV. MAIJODRYINI, p. 1291. 



cc. Front coxal cavities without fissure ; form oval or oblong, convex. 



Tribe V. ORCHESIINI. p. 1291. 

 mi. Next to last joint of front and middle tarsi excavate and emarginate. 



more or less lobed beneath; front tarsi of males dilated. 

 /. Tarsal claws simple or very slightly broader at base; thorax as wide 



at base as elytra. 



(j. Head nut constricted behind. Tribe VI. MEI.ANDRYINI. p. 1295. 

 !,!/. Head suddenly constricted behind the eyes; small species, not over 

 ~> mm. in length. Tribe VII. SCRAPTIINI, p. 1299. 



ff. Tarsal claws with a broad tooth or lobe at base. 



It. Middle coxal cavities open on the outer side: head not prolonged; 

 thorax as wide at base as elytra, its side margins entire, acute. 



Tribe VIII. NOTHINI, p. 1301. 



///(. Middle coxal cavities enclosed by the sterna; head more or less 

 prolonged in a beak ; thorax not as wide at base as elytra, its 

 margin evident at base only. Tribe IX. MYCTEKINI. p. 1302. 



Tribe I. TETBATOMINI. 



This tribe comprises small, oval convex forms living- in fungi 

 and having the last three or four joints of antenna 3 much enlarged, 

 nearly equal in size and forming a loose club; tibial spurs small; 

 next to last tarsal joint not lobed, claws simple, coxa? all separated 

 by their respective sterna. Casey, locality cited, has divided the 

 tribe into five genera, three of which are represented in the State, 

 while a single species of another may occur. 



