MONOCESTA. 477 



forms part of the sixteenth group of Chapuis's arrangement, the " Ccelomerinse." From 

 Ccelomera proper, Monocesta is distinguished by the proportionate different length of 

 the joints of the antennae, the third and fourth joints being nearly equal ; in Coelomera 

 the third joint is very long. 



Monocesta has its headquarters in Tropical South America ; one species, however, 

 extends to the United States. Nearly thirty species have been described. 



1. Monocesta ducalis. (Tab. xxvil. fig. l.) 



Monocesta ducalis, Clark, Ann. & Mag. Nat. Hist. 3rd ser. xvi. p. 265 \ 



Eab. Mexico \ Peras, Coscomotepec, Orizaba (Salle), Jalapa (Edge) ; Guatemala 

 (Salle) ; Nicakagua, Chontales (Janson); Panama, Volcan de Chiriqui (Champion). 



Many specimens. The description given by Clark scarcely conveys a clear idea ot 

 the elytral pattern of this species : the elytra are pale fulvous with a broad blue or 

 green transverse band at the base, and a large similarly coloured patch of variable size 

 below the middle ; the posterior margin of the basal band is nearly straight, and 

 extends nearly to the middle, but never to the lateral margin, which remains of the 

 ground-colour ; the space dividing the band and the spot is of variable size — in one 

 specimen (from Nicaragua) it is extremely narrow, and nearly the entire disc blue. 

 Clark describes the head as punctured, which is only the case near the middle portion ; 

 the vertex is divided by a longitudinal groove; the third joint of the antennae is 

 slightly longer than the fourth ; the underside and legs are of a dark metallic bluish 

 colour, not black as Clark says. I have examined nearly a hundred specimens of 

 M. ducalis, and in none of them do I find the basal elytral band extend to the lateral 

 margin. 



2. Monocesta jansoni. (Tab. xxvil. fig. 2.) 



Broadly ovate, dilated behind, blackish-blue ; elytra opaque, fulvous, pubescent, a broad transverse band at the 



base (extending to the sides) and a large round spot below the middle, dark blue, 

 length 8 lines. 



Hah. Nicaeagua (Salle), Chontales (Belt, Janson). 



It will be sufficient to point Out the differences between M. jansoni and M. ducalis. 

 In M. jansoni the elytra are opaque instead of shining, on account of the very fine and 

 close fulvous pubescence; the basal transverse band extends always to the lateral 

 margins, and is more or less deeply dentate on its posterior edge ; the posterior blue 

 spot is of a more regularly rounded shape, and never extends to the suture, the reverse 

 being the case in M. ducalis ; the underside and the legs are nearly black. M. jansoni 

 also averages rather larger in size than M. ducalis. 



There are seven specimens before me, all of which exhibit the above described 

 characteristic differences. 



