38 Key to Families of North American Insects. 



83. Body broadly oval, convex; tropical beetles. (Aphaenocephalus) (DISCOLOM- 



IDM, PSEUDOCORYLOPHIDM) APHiENOCEPHALIDiE 



Body more elongate, the prothorax narrower than the elytra and often marked 

 with elevated lines. (Corticaria, Cartodere, Melanophthalma) (PI. 7, fig. 



145) LATHRIDilD^ 



8-1. Front coxae subtransverse; maxillae with a single lobe. (Tribe Sniicriptini, a 



rare beetle from Florida) (Smicrips.) NITZDULIDiE, part 



Front coxae small, rounded; maxillae bilobed; small, flattened bark beetles. 

 (Monotoma, Bactridimn.) MONOTOMLD.^ 



85. Tarsi apparently two-jointed, but with the second and third joints very minute. 



(PI. 7, fig. 1G3). (See couplet 69) ADIMERID^ 



Tarsi one-jointed; minute tropical beetles with four-jointed antennas (Cyatho- 

 cerus) CYATHOCERIDyE 



86. Front coxal cavities closed behind (PI. 6, fig. 119) 87 



Front coxal cavities open behind (PI. 6, fig. 114) 93 



87. Tarsal claws simple 88 



Tarsal claws pectinate; usually elongate, convex thinly silky-pubescent beetles. 



(Hymenorus, Mycetochares) {ALLECULID.E) CISTELIDiE 



88. Ventral segments all freely movable (If the mesosternum is carinate, compare 



some rare Silphidae, couplet 60) 89 



First two to four ventral segments more closely connected together, more or 

 less fused and immovable 91 



89. Front coxal cavities separated by the prosternum (PI. 6, fig. 119) 90 



Antennae eleven-jointed; front coxal cavities confluent (Othnius) OTHNIID.^ 



90. Elytra entire; small convex beetles (Sphindus) SPHINDIDiE 



Elytra truncate, exposing the pygidium; small flattened beetles (males of 



Rhizophagus) (see couplet 26) NITIDULIDiE 



91. Five ventral segments 92 



Six ventral segments, the first two immovably united; a small black beetle 



from Alaska. (.Sgialites.) lEGlMAT'^DJE. 



92. Penultimate joint of tarsi spongy pubescent beneath; front coxa; prominent; 



slender, elongate species with cylindrical prothorax, usually of somewhat 



metallic color. (Arthromacra, Statira.) LAGRnD.^ 



Penultimate joint of tarsi not spongy pubescent beneath; front coxae short, not 

 projecting from the cavities; beetles of varying form, oval, elongate, or even 

 pedunculate, usually black or dark colored with more or less bead-like 

 joints to the antennae. (Nyctobates, Tenebrio [7". molitor. Mealworm] 

 Blapstinus, Platydema, Diaperis, Eleodes) (PI. 5, fig.105) TENEBRIONIDiE 



93. Head not strongly or suddenly narrowed or constricted behind the eyes ... .94 

 Head strongly and suddenly constricted behind the eyes 99 



94. Middle coxae not noticeably prominent 95 



* Middle coxae very prominent; prothorax without lateral margin; penultimate 



• tarsal joint dilated and with a dense brush of hairs beneath; soft-bodied 

 species. (Nacerdes, Asclera, Copidita.) CEDOMERIDiE 



