498 Mr. F. Smith's Descriptions of 



genera ; the genus Tetragona therefore cannot be retained. M. 

 Guerin Meneville observes, in the " Iconographie du Regne 

 Animal," that several authors do not separate MeUpona and 

 Trigona ; this is true, but I am incHned to believe this has arisen 

 from the fact of their not having been acquainted with a sufficient 

 number of species. To me it appears that nature herself has 

 separated them ; for although both genera are found abundantly 

 in the New World, yet not a single species of the genus MeUpona 

 has, I believe, yet occurred in the Old World ; whereas a great 

 many species of Trigona have been discovered there ; they are by 

 no means uncommon in India, Africa, Austral^ia, or the Islands of 

 the eastern Archipelago, &c. This circumstance appears to me to 

 offer a strong argument in favour of their separation. 



The general appearance of the bees that compose the two 

 genera is at once obviously different ; those belonging to the 

 genus MeUpona have a close resemblance, in many instances, to 

 those of the genus Osmia, to which the species of the genus 

 Trigona have not the least resemblance. 



The only distinctive generic character, proposed by Latreille 

 for the separation of these genera, is their having either dentate 

 or edentate mandibles ; the examination of a large number of 

 species proves that this character cannot be accepted as of generic 

 value ; I believe it only characterizes species of peculiar habits of 

 economy. Of the fourteen species of Trigona described in the 

 present paper, four only have toothed mandibles; yet the 

 general habit of the species at once denotes that they all un- 

 doubtedly belong to the same genus. I have inspected the oral 

 organs of a considerable number of species, and all agree in having 

 the same number of joints in the labial palpi ; but those which I 

 have examined with toothed mandibles, have the palpi as long as, or 

 even longer than, the tongue, the palpi being set with a few long- 

 ish hairs ; but I have not found any baving edentate mandibles 

 with pubescent palpi ; I am here alluding to species of Trigona. 



The form of the palpi differs considerably in the various species 

 that I have examined ; in some, the two elongate basal joints of 

 the labial palpi are narrow, and only slightly widened at their 

 base ; others are more widened at the base, and have also a broad 

 thin semi-transparent flattened margin. The tongue also varies 

 greatly in its relative proportion to the labial palpi, being longer 

 or shorter in different species. The same differences also obtain 

 in the genus MeUpona, but in a greater degree ; the tongue being 

 sometimes nearly twice as long as the labial palpi, and pubescent 

 at the apex ; in others it is about equal in length to the palpi ; 



