1956 ] Brown — African Tetramorium 75 
The Relationship of Two African Tetramorium Species 
(Hymenoptera: Formicidae). — During 1955, Mr. Thomas 
Gregg, a student at Harvard University, made for me a 
small but select collection of ants in the vicinity of Epulu, 
Ituri Forest, in the Belgian Congo. The ants have been 
deposited in the Museum of Comparative Zoology at Har- 
vard. Among the series were two nest samples of Tetra- 
morium, of which the workers were a striking yellow in 
color, but with the alitrunk and petiole a contrasting 
blackish or piceous hue. 
It was found that both series agreed in general with 
the description of T. coloreum Mayr (1901, Ent. Tidskr., 
21: 273, worker; type loc. : Mungo R., Kamerun), while 
one of them corresponded more particularly to that of 
T. coloreum var. postpetiolata Santschi (1919, Rev. Zool. 
Afr., 7: 88, worker; type loc.: Penghe, Belgian Congo). 
The two series, while very similar at first glance, are 
distinguished by a number of characters. As noted by 
Santschi, postpetiolata has the postpetiole markedly broader 
than long and with a smooth and shining surface (in 
coloreum, not or just barely broader than long and with 
irregular longitudinal costulae or striae on the disc, ex- 
tending onto the base of the gaster). Santschi also 
mentioned that the posterodorsal petiolar face is more 
rugose (and opaque) in postpetiolata. In addition, in my 
postpetiolata specimens, the petiolar node is distinctly 
thicker from front to rear, the alitrunk is narrower, lower 
and less suddenly constricted behind, and the propodeal 
and triangular metapleural teeth are both distinctly shorter 
than in coloreum. Also, in postpetiolata, the erect hairs 
are slightly longer, more abundant (particularly on pe- 
tiole), more slender and have more tapered apices. 
Since Santschi’s chief distinctions appear to be main- 
tained, and even supplemented, in the present sympatric 
samples, I am suggesting that Tetramorium postpetiolatum 
be granted new status as a species. 
Mr. Gregg took the T. coloreum nest at Epulu from the 
upper side of a log covered with earth in the rain forest. 
The T. postpetiolatum series was taken in this vicinity, 
also in rain forest, in the soil beneath leaf litter. W. L. 
Brown, Jr., Museum of Comparative Zoology. 
