PALCEOTHONA. 377 



PALCEOTHONA. 



Body oblong ; eyes entire ; palpi filiform ; antennae elongate, slender, the third joint distinctly longer than the 

 second ; thorax transverse, the sides rounded, the posterior margin often with a small depression at the 

 middle ; scutellum large, triangular ; elytra widened behind, depressed below the base, finely punctured,, 

 the punctures often arranged in close rows ; legs rather long and slender ; posterior tibiae simple, armed at 

 the apex with a small spine ; first joint of the posterior tarsi longer than the two following joints united ; 

 claws appendiculate ; anterior coxal cavities open. 



The genus here proposed, although not possessing any very striking peculiarities as 

 regards structure, seems still sufficiently distinct to justify its separation from Aphthona 

 and Phyllotreta. The species included in Palceothona have a rather depressed, elongate,, 

 and posteriorly widened appearance ; the antennae are much longer and more elongate 

 than in the above-named allied genera, their third joint especially being in most 

 instances nearly three times the length of the second ; the thorax is more transverse, 

 the posterior margin is sinuate and has a kind of fovea at its middle, more or less 

 distinct; the elytra also have the base somewhat raised, this elevation being bounded 

 behind by a depression, and the scutellum is large and broad. These differences may 

 possibly prove to be of insufficient importance to justify a separation of Palceothona 

 from Aphthona, if intermediate forms should be discovered ; but at present I think it is 

 advisable to retain Palceothona for the sake of an easier determination of the numerous 

 species contained in the preceding genera as far as it relates to Central- American forms. 



1. Palaeothona rugifrons. (Tab. XXII. fig. 6.) 



Below black ; head, basal joints of the antennae, thorax, and the anterior femora fulvous ; head rugosely 

 punctate ; thorax impunctate ; elytra dark blue, scarcely visibly punctured. 



Lengjfch If line. 



Head not longer than broad, the vertex rugosely punctured near the eyes ; frontal tubercles short but distinct ; 

 carina flattened and joined to the clypeus ; apical joints of the palpi piceous ; antennae slender, black, 

 the first three joints fulvous, the others rather strongly pubescent ; thorax more than twice as broad as- 

 long, the sides strongly rounded before the middle ; the anterior angles broadly oblique and rather 

 strongly constricted behind; posterior margin depressed in front of the scutellum, surface entirely 

 impunctate, fulvous ; scutellum black ; elytra widened behind, the basal portion strongly raised, surface 

 covered with minute punctures (when seen under a very strong lens) ; underside and legs black, the latter 

 covered with yellowish pubescence, the anterior femora and sometimes the intermediate below, fulvous. 



Hab. Mexico, Jalapa {Edge). 



2. PalsBOthona guatemaJensis. 



Below piceous ; head, thorax, legs, and antennae fulvous ; apices of the posterior femora piceous ; head and 

 thorax impunctate ; elytra metallic blue, finely and closely semipunctate-striate. 



Var. Apical joints of the antennae and the posterior legs black. 



Length l|-2 lines. 



Head impunctate, with a single fovea near the inner margin of the eyes ; frontal tubercles scarcely raised, but 

 deeply divided in front ; carina short and distinctly raised ; antennae two thirds the length of the body r 

 third joint more than twice as long as the second, fourth loDger than the third ; thorax not more than 

 twice as broad as long, the sides strongly rounded at the middle, anterior angles blunt and scarcely 

 oblique, the surface more convex than in P. rugifrons, impunctate, with the exception of a few punctures- 



biol. CENTR.-AMEE., Coleopt., Vol. VI. Pt. 1, August 18 85. 3 c 



