AMERICAN COLEOPTERA. 277 



tibiae, and is, I am disposed to believe, due rather to similarity of 

 habits and environment rather than to a community of origin. 

 Ptilinus has, however, become so strongly individualized that it 

 does not fit well anywhere in the series, and since similarity of 

 habitus with the Bostrychides, whatever its origin, may fairly count 

 for something, it has seemed best to leave the genus where it was 

 placed by LeConte. 



European systematists have not recognized in Ptilinus the type 

 of a distinct tribe, the genus having long been assigned by them to 

 the Xyletini, the genera of which, according to the system there iu 

 vogue, differ from the Anobiini in the three outer joints of the 

 antennae not being elougated. In view of the instability of an ten - 

 nal form in y;enera otherwise closely allied, this method of division 

 seems to be an unfortunate one, and in this case brings together 

 such discordant elements as Tnjpopitys, Ptilinus and Lasiodenuu. 



The genus Plumaria, represented by a single species from the 

 Caucasus, agrees with Ptilinus in the structure of the anterior tibiae, 

 in the general shape of the body, and in the disparity in form in the 

 sexes, and should doubtless be associated with it wherever placed. 

 Euceratocerus, associated by LeConte with Ptilinus, should not so 

 stand, and has been removed (vid. ante) to the Anobiini. The 

 antennae are pectinate iu the male in about the same degree as iu 

 Ctenobium and Xeranobium, and are not to be compared with the 

 flabellate form prevailing in the male of Ptilinus. It should be 

 remarked that the tabular character given in the Leconte and Horn 

 Classification for the separation of the Ptilinini from the Anobiini, 

 viz.: "Eves distant from the prothorax " is fortuitous and totally 

 unreliable. The principal characters of this tribe are given in the 

 table on page 128, or will be found in the generic diagnosis below. 



PTILINUS Geoffrey. 



Mentum transversely subquadrate, very little narrowed anteriorly; 

 terminal joints of both maxillary and labial palpi elongate-cylindri- 

 cal, a little thickened before the base; penultimate joint of maxil- 

 lary palpus short, moderately widened apically ; of labial palpus 

 elongate- clavate and a little arcuate; the palpi more hairy than 

 usual. Antennae 11-jointed, first joint moderately elongate and 

 distinctly curved; second small, as wide as long; third elongate- 

 cylindrical, with a basal process as long as the joint itself in the 



TRANS. AM. ENT. SOC. XXXI. JULY, 1905. 



