2 Memoirs on the Coleoptera 



longation, separation of the anterior coxae, armature of the femora, 

 relative concealment of the pygidium and freedom of the tarsal 

 claws, with many others of subsidiary or special nature, such as 

 tubulation of the prothorax, freedom of the scutellum and nature 

 of the pubescence and sculpture. There are very few sections of 

 the Coleoptera where it is less practicable to devise sets of definitive 

 group characters, which shall be reasonably constant, than it is in 

 the Barinae, and considerable reliance must therefore be placed upon 

 habitus, in aggregating genera to form groups or tribes. The form 

 of the beak and mandibles, for example, depends to a great extent 

 upon the life habits, as can be seen in the Balanimis-Mke beak 

 which occasionally appears in many of the tribes, even when that 

 part is usually and typically short, thick and compressed, as in the 

 case of Genestus in the Diorymerini and Costovia in the Optatini, 

 and in the very peculiar beak and mandibles of Matrilia, of the 

 former tribe, and Nedestes of the Centrinini, where the mandibles 

 have the most extraordinary development. The mandibles may, 

 in fact, assume very diverse forms within the same tribe, so that no 

 dependence can as a rule be placed upon them through large groups 

 of genera. The beak in the Centrinini and Madarini is more 

 frequently rather long, slender and arcuate, but in Neplaxa, Zygo- 

 zahstes and some others, it assumes a remarkably specialized form, 

 and, in Tropidobaris, it has a high basal crest or keel in both sexes. 

 In the Coleomerini and Ccelonertini, the beak is as securely sheltered 

 in repose within a tightly fitting channel, as it is in the Crypto- 

 rhynchinae. It is singular, however, that with all this perplexing 

 diversity of development in nearly all the special parts and organs, 

 there are two features that, so far as I know personally, are abso- 

 lutely constant; these are the uniformly 7-jointed antennal funicle 

 and the simple tarsal claws. In regard to the former Mr. Champion 

 has described a 6-jointed funicle in the Central American genus 

 Odontobaris, but there is no such case among the Brazilian forms, 

 so far as yet discovered. It sometimes happens, however, that the 

 seventh joint is densely pubescent and so broad and close to the 

 club as to be differentiated therefrom only under high amplification 

 and careful observation. The constant presence of the ascending 

 mes-epimera, truncating the elytral humeri, may be conceded, as 

 this is the chief distinguishing feature of the Barinae, but even here 

 there is notable variability in degree of development. In many 

 cases the epimera are conspicuously visible from above in the re- 

 entrant angle between the elytra and prothorax, but in other 

 instances there is no trace of them from a dorsal viewpoint, and, 

 in the genus Neplaxa, they are very feebly developed. Moreover, 

 I believe this character is occasionally observable in some other 

 subfamilies besides the Barinae, as for instance in certain Zygopides. 



