TENEBUIOXIDAE. 



577 



Outer joints of antennjp perfoliate, antennw shorter than head and 



thorax. 2. 



Outer joints of antenn;e trianguhir, antenna; slender, longer. 10. 



2. Epipleune entire. 3. 

 EpipleurjB not attaining the tijis of elytra. 5. 



3. Epipleur;e not narrowed to apex. Polypleurus. 

 Epipleune narrower at apex. 4. 



4. Mentum witli small, lateral inflexed lobes. Nyctobates. 

 Mentum without lateral lobes. Iphthimus. 



5. Intercoxal process of abdomen broad, truncate. Ccelocnemis. 

 Intercoxal process narrow, acute. 6. 



6. Eyes feebly eniarginate, broad at middle. 7. 

 Eyes deeply emarginate, narrow at middle. i). 



7. Femora strongly clavate. Merinus. 

 Femora slender. 8. 



8. Hind tarsi long. Upis. 

 Hind tarsi short. Haplandrus. 



9. Mentum trilobed, middle lobe prominent. Centronopus. 

 Mentum flat, rounded in front. Cibdelis. 



10. Epipleurje attaining the tip of the elytra. Glyptotus. 

 Epipleura? not attaining the tip. 11. 



11. Anterior tarsi of male not dilated. Rhinandrus. 

 Anterior tarsi of male feebly dilated. 12. 



12. Anterior margin of front reflexed. Scotobates. 

 Anterior margin of front not reflexed. Xylopinus. 



Of these genera Coeloenemis, Cibdelis, and Centronopus are 

 Californian ; Iphthimus is represented on both sides of the con- 

 tinent, Rhinandrus in Lower California,' the other genera belong 

 to the Atlantic region. Centronopus, of the above table, is Sco- 

 tobaenus of the preceding edition of this work, while Scotobates 

 contains those species formerly considered Centronopus. Pachy- 

 urgus has been omitted, the species on which it is founded being- 

 foreign to our fauna. 



Singular se.xual characters are observed in the anterior and 

 middle tibiae of Scotobates, in the anterior tibiae of Xylopinus, 

 and in the anterior and hind tibisfi of Merinus; in the last named 

 the hind femora are also armed with a small tooth. No very- 

 marked sexual differences are seen in Upis, Haplandrus, or Cib- 

 delis, nor in the genera with entire epipl(Mira3. In Ccelocnemis 

 the hind tibiie of the male are furnished with a dense brush of 

 hair on the inner face near the tip. 



Group II. — Tenebriones. 

 In this group the body is elongate oval, or elongate, and 

 winged ; the hind coxae are moderately distant, the legs are 



