100 
Psyche 
[June 
The affinities of the Melissotarsini to other tribes of 
Myrmicinse are very obscure. Forel at first regarded Rho- 
palomastix as allied to Solenopsis, but on receiving the 
worker at once recognized its close relationship to Melis- 
sotarsus. He believed, however, that “both genera are un- 
doubtedly primitive Myrmicines, allied to the Ponerine 
group Cerapachyi.” In view of the extraordinary special- 
ization of the structural characters in both genera of Melis- 
sotarsini, this relationship can hardly be maintained. It was 
evidently suggested by purely superficial resemblances in 
general habitus to forms like Cylindromyrmex, Simopone, 
etc. which also burrow in wood. Emery, who had carefully 
studied Melissotarsus, when he came to revise the classifica- 
tion of the Myrmicinse for the “Genera Insectorum” (1921 
p. 8) confessed his inability to establish the affinities of the 
Melissotarsini and a few other aberrant Myrmicine genera. 
He says: “Myrmicaria, Stereomyrmex, Cardiocondyla and 
especially the Melissotarsini are very specialized and isol- 
ated ants. In the present state of Myrmecology it is abso- 
lutely impossible to say anything about their affinities. I 
am of the opinion that the Melissotarsini are very prim- 
itive, but profoundly adapted to particular conditions of 
existence (thorax without sutures, antennae, lack of spurs, 
very small size, etc.). At any rate this group is very aber- 
rant.” In the “Genera Insectorum” Emery placed the Melis- 
sotarsini next to the Stereomyrmicini, which they somewhat 
resemble. In my opinion there are also vague affinities be- 
tween the Melissotarsini and the Myrmecinini, especially in 
the wing-venation and the structure of the head of the male, 
though the mesonotum of the male Myrmecina possesses 
notauli which are absent in the Melissotarsini. 
In all probability the Melissotarsini, which now comprise 
only half a dozen species, are the last survivors of some very 
ancient Myrmicine stock. Their antiquity is attested by their 
rare and sporadic occurence in a rather circumscribed geo- 
graphic area. Evidently the Indomalayan genus Rhopalo- 
mastix is more primitive than Melissotarsus, which is 
known only from the warmer parts of Africa and Madagas- 
car. In both genera, however, the characters of the worker, 
particularly the diminutive size, compact, subcylindrical 
