DISONTCHA. 305 



case in Lactica. Clark says that the claws are simple, which is not the case, as they are 

 decidedly appendiculate. Almost the same difficulties are experienced in the separation 

 of the species as in Ealtica, their coloration being, for the most part, very similar, and 

 consisting of a testaceous ground-colour striped with black. There are, however, 

 species with metallic blue and green elytra, and others with transverse black markings ; 

 these two latter forms I have considered first in the present monograph. 



1. Disonycha collata. 



Crioceris collata, Fabr. Syst. El. i. p. 463 1 ; Suffr. Wiegm. Arch. 1868, p. 180 \ 

 Altica collata, Oliv. Ent. vi. p. 702, t. 4. fig. 61 3 ; Illig. Mag. vi. p. 126*. 



Eab. Noeth America 134 . — Mexico, Monclova, Saltillo in Codahuila (Br. Palmer), 

 Ciudad in Durango (Forrer), Jalapa (Edge), Cordova, Cosomatepec, Oaxaca, Yolos, 

 Puebla, Guanajuato, Capulalpam (SalU); Guatemala (coll. Salle', Jacoby), near the 

 city, Purula, Capetillo, Duefias (Champion) ; Costa Rica ( Van Patten). 



This is evidently a widely distributed and not uncommon, as well as variable, species 

 The descriptions of Fabricius and Olivier give the elytra as " kevis." Von Harold says 

 (Coleopt. HefteJ that the specimens from North America are distinctly punctured. The 

 many specimens before me from the above localities show great variation in this respect, 

 from nearly impunctate to distinctly punctured elytra. The colour of the legs seems 

 equally variable ; and, although Fabricius gives the femora as yellow, I have many 

 specimens for comparison which have only the base of the femora flavous, the rest black 

 (in which they agree with the description of B. collaris) ; some have the legs entirely 

 black. In all, however, the lower part of the head is flavous, the vertex being metallic 

 greenish, which is the colour of the true B. collata. In spite of this diversity I look 

 upon all these specimens as representing but varieties of one species. 



2. Disonycha nigripes. (Tab. XVIII. fig. 7.) 



Below testaceous ; antennae and legs black or piceous ; head and thorax flavous, obscurely marked with 



piceous ; elytra impunctate, violaceous blue. 

 Length 2 lines. 



Eab. Costa Bica, Cache (Bogers); Panama, Volcan de Chiriqui, David, Tole 

 (Champion). 



Larger than B. collata, and distinguished by the following differences : — The head is 

 entirely flavous without the coarse punctuation, with a small but deep fovea in front of 

 each eye ; the frontal tubercles are entirely absent ; the carina is strongly raised, and 

 widened into the clypeus ; the antenna? are rather long, quite half the length of the 

 body, the fourth joint being much longer than the third ; the sides of the thorax are 

 nearly straight, thickened at the anterior angles, the surface without any distinct basal 

 depression or transverse groove, but the posterior angles are, as usual, obliquely shaped ; 



biol. cenet.-amer., Coleopt., Vol. VI. Pt. 1, June 1884. 2r 



