544 FAMILY XVIIl. — EROTYLIDiK. 



d. Last joint of palpi widely tiatcliet-sbaped ; thorax yellow with four 



black spots; length 7-.S mm. V. Ischyeus. 



d<l. Last joint of palpi oval or slightly triangular ; thorax yellow or black, 



rarely with two spots ; length less than mm. 



c. Middle area of mentum large, transverse. VI. Mycotbetus. 



er. Middle area of mentum small, triangular. VII. Tbitoma. 



II. Ploeosoma Woll. 18.54. 



This geniLS is represented in the eastern Ignited States and In- 

 diana by a single very small brown species. 



lOni (;^.212). PLCEOsoiNfA PL>:("j'AT.\ Lcc Trans. Amer. Ent. Soc, "\'. 187."i. 

 171. 

 Oval, rather strDnuiy ciinvc.x. Uniform dark chestnut-) >i-( jwn ; antenufe 

 and Icfis paler. Thorax t\\ ice as wide as lon.i;. finely and sparsely punctate. 

 Klylra distinctly l)nt i-atlicr s|].ii-scly and irregularly punctate, and nar- 

 rowed to a rounded 'A]\c\. Lciijitli 2 2,.''i nnn. 



Sdiithern two-tliii-ds of Stale; eomiiion. Hibernates. April 0- 

 Deeember 3. Gregarious in winter and early spring beneath bark, 

 especially that of elm and willow. 



III. Dacne Latr. 179G. (Gr.. "bite or sting.") 



Tbis genns is represi'iiti-d in the United States by three small 

 species, one of which oci nrs in Indiana. 



10:;.S (:!2i:'.). D.scne 4-\iAcr],A'JA Say, T.osl. .T(aH-n. Nat. Ilisf., I. 1S:i.'',, lOK; 

 ibid. II, (U5. 

 Obloug, parallel. P.lack ; elytra each with a niuml rcddish-ycllcw spot 

 on humerus and another at ape.x ; beneath piccims or dark reddish-brown, 

 the antenme, le^'S and dyiieiis paler. Head and thorax chjsely but spars(-ly 

 punctate; elytra with nuiiieruus rows of fine punctures. Length 2..':>-:'..2 nnn. 



Throughout th(> State, frecrnent in the sonthern counties; less so 

 northY-ard. April ]5-Septeinber 21. Occurs in fungi. 



IV. :ME(!ALonAfNE Crotch. 1S73. (Gr., "large -f- bite.") 



Here lielong the largest species of the family, handsome black 

 and yellow forms, having the fourth .ioint of tarsi smaller but dis- 

 tinct; last joint of palpi sul)cylindrical and the mentum triangular. 

 Three species are known from the Ignited States, all of which occur 

 in Indiana. 



KEY TO INI)I.\NA SPECIES OF ,\[EQALODACNE. 



rt. Elytra withmil Pdw s of pnnclurcs; loimlli l.S-21 nnn. 1040. iif.ros. 



aa. Elytra with rows of fine punctures. 



