MEGASCELIS.—MASTOSTETHUS. 57 
clothed with short fulvous pubescence, testaceous with a pale metallic green gloss, each with a sub- 
quadrate purplish or bluish spot at the base and a smaller one below the middle; underside and legs 
fulvous. 
Hab. Panama, Bugaba, Caldera in Chiriqui (Champion). 
This pretty little species, of which there are two specimens before me, greatly 
resembles in the elytral markings M. quadrimaculata, Bates, from the Amazon region. 
The latter, however, differs from the Panama insect in the nearly impunctate head 
and in its generally larger size; it also has the thorax much less closely and finely 
punctured. 
MASTOSTETHUS (p. 19). 
Mastostethus balteatus (p. 19). 
Mastostethus nigrocinctus, huj. op. p. 20. 
To the locality given, add :—Muexico, Cordova, Capulalpam (Sallé), Jalapa (Hoge), 
Cuernavaca (H. H. Smith); Guatemata, San Gerénimo, Coban, Panima, San Juan, 
Cubilguitz, Purula and Chacoj in Vera Paz, Las Mercedes (Champion); Costa Rica 
(Van Patten); Panama, Bugaba, Volcan de Chiriqui (Champion). 
After comparing carefully more than fifty specimens I can only come to the con- 
clusion that If. nigrocinctus is a variety of M. balteatus. The two insects in question 
have been separated merely by slight differences in coloration, which cannot be con- 
sidered a character of distinction, as the many varieties enumerated by Lacordaire of 
M. nigrocinctus prove. M. balteatus is most variable, and specimens occur which are, 
with the exception of the underside, entirely fulvous. The punctuation of the elytra 
does not furnish a distinctive character between the two so-called species. 
Mastostethus cingulatus (p. 20). 
M. cingulatus is undoubtedly nothing but an immature form of either M. balteatus 
or WM. bilobus ; I have several specimens agreeing with the type and also intermediate 
degrees in coloration before me, and as no structural character has been pointed out by 
Lacordaire, and the species is a most variable one in regard to colour, I do not think it 
any advantage to retain it as distinct. 
Mastostethus bilobus (p. 20). 
To the localities given, add :—GuatEMaLA, Yzabal (Sal/é), Panzos, Teleman, and San 
Juan in Vera Paz, El Reposo (Champion) ; Panama (Boucard), San Lorenzo (Champion). 
It seems to me also doubtful whether UW. bilobus should be looked upon as anything 
but a variety of WZ. balteatus, from which it does not differ except in the colour of the 
thorax and underside. There are several specimens before me which show intermediate 
stages of variation in this respect, and scarcely two are exactly alike ; structural differ- 
BIOL. CENTR.-AMER., Coleopt., Vol. VI. Pt. 1, Suppl., November 1888. i 
