32 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



visible under higher magnification. The coarser punctures are sparse, 

 deep and distinct, the minute ones closely placed giving this part of 

 the pronotum a more opaque appearance. The posterior margin is 

 slightly arcuate. Immediately anterior to the posterior margin there 

 is an impressed line giving the intermediate space the appearance of 

 a low ridge. This raised margin served as one of the main characters 

 in placing this genus near Pityophthorus and allied genera. The pro- 

 notum is covered with inconspicuous hairs which are longer and 



Fig. 14. — Gnathotrichus sulcatus Lee. : Prothoiax, ventral aspect. 



a, anterior foramen; b, posterior foramen; c, anterior margin of pronotum; d, posterior 

 margin of pronotum; CxC, coxal cavities; Epm, epimeral area; Eps, episternal area; ICP. 

 intercoxal process; Peps, preepisternal area; Pst, poststernal area; St, sternal area; T, 

 tergum or pronotum. 



coarser anteriorly. Posterior to the summit occurs a shallow trans- 

 verse impression. The lateral limitations of the pronotum are not 

 clearly defined Init near the postero-lateral angle is a longitudinal ridge 

 which may be considered as a remainder of the pleuro-notal suture. 



Pleural area. — ^The propleural area (fig. 14) is represented as one 

 continuous plate in the shape of a trapezium of which the base is 

 formed by the remainders of the pleuro-notal suture. Ventrally the 

 pleural area is completely fused with the prosternum (St). Externally 

 no sufficiently distinct lines are present to justify the distinction of 

 subdivisional plates as episternum, epimeron, etc. Nevertheless there 

 can be distinguished three parts of different structure which one may 

 call the preepisternal (Peps), the episternal (Eps) and the epimeral 



