REVISION OF THE TRIBE PAEDERINI — ^BLACKWELDER 95 



These characters seem to me to be superficial and of little use in 

 generic divisions, at least. It should also be pointed out that, although 

 the labrum does present some characters of value, especially for sub- 

 genera, it cannot be relied on blindly at aU times. The slight differ- 

 ences in the labra are generally accompanied by more important or 

 more readUy usable characters in other parts of the body. 



In the present study there are several weak points that should be 

 pointed out. The character in couplet 16 involving the ctenidia of 

 the apex of the posterior tibia is not entirely satisfactory. I have 

 been unable to find another to replace it, and it apparently holds for 

 the species examined. The fundamental character of umbUicate 

 punctation is not sufficiently understood to permit the use of a satis- 

 factory terminology. This type of sculpture undoubtedly is closely 

 related to the setigerous tuberculi, which are rather common. Cer- 

 tain inconsistencies will appear if the use of this term is misunderstood. 

 Care must be exercised in couplet 43. The sternite may be (and 

 usually is) touching the hypomera even though not united to it. 

 Often a narrow space is visible between them, whereas in the connate 

 species the sternite is obviously united to the inner side of the 

 hypomera. 



KEY TO THE GENERA AND SUBGENERA OF THE PAEDERINI 



1. Prosternum not dilated under front coxae as far as hypomera 2 



Prosternum expanded laterally and caudally, either connate 



with hypomera or very narrowly separated from them 43 



2. Anterior coxal cavities closed by an independent sclerotization 



behind sternite, which extends laterally to or almost to 



hypomera 3 



Anterior coxal cavities entirely open behind 5 



3. Eyes entirely lacking Scotonoraus 



Eyes present, normal 4 



4. Elytra well developed; length 4 to 10 mm Leptobium 



Elytra very much abbreviated; length over 15 mm Dolicaon 



5. Antennae anteriorly flexile and strongly geniculate at first joint, 



basal segment very much elongate 6 



Antennae posteriorly flexile, not strongly geniculate, basal seg- 

 ment not very elongate 14 



6. Neck less than one-fourth as wide as head 7 



Neck more than one-fourth as wide as head 8 



7. Head greatly prolonged posteriorly in a slender neck Ophites 



Head not prolonged posteriorly in a slender neck Scopaeodes 



8. Gular sutures united throughout their length Monocrsrpta 



Gular sutures separate throughout their length 9 



9. Elytra with a pleural fold near side margin 10 



Elytra without trace of a pleural fold 12 



10. Neck entirely unconstricted above and below Aderobium 



Neck abruptly constricted across dorsal surface 11 



11. Integuments highly polished, very sparsely punctate, without 



ground sculpture Lissobiops 



