35. Formicide from Easter Island and Juan Fernandez. 
By 
WILLIAM MORTON WHEELER. 
The ants taken by Mr. K. BACKSTROM, zoologist to Professor SKOTTSBERG’s 
expedition to Easter Island and Juan Fernandez comprise only seven small 
forms, all belonging to well known »tramp», or vagabond species of Old World 
origin, with the single exception of Ponera trigona var. opacior, which is widely 
distributed in tropical and subtropical America. It is therefore interesting to 
note that the affinities of the ant fauna of these islands, so far as they are 
revealed by the collection, are very largely with Polynesia. This is clearly 
indicated by such species as Prenolepis bourbonica and obscura, Plagiolepis 
mactavisht and Cardiocondyla nuda which have not been taken in America. I 
have noted in the following paragraphs the known range of each of the seven 
forms taken by the expedition. 
1. Ponera trigona Mayr. var. ofacior Forel. § 2 &. — »Under stones.» 
The types of the species are from Sta. Catharina, Brazil, and of those the var. 
opacior from St. Vincent, West Indies. I have seen specimens of the latter 
from Concepcion, Chili (R. THAXTER), Texas, California, Florida, Mexico and 
numerous stations in the West Indies. It seems to be very common in the 
Argentine. FOREL has described a subsp. conveaiuscula from Queensland, 
Australia. — Easter Island. 
2. Cardiocondyla nuda Mayr. subsp. mznutzor Forel. 
Worker. Length I,e—I,8 mm. 
Differing from the typical zwda in its smaller size, in having the head 
more rectangular, with more pronounced posterior corners, and the thorax, 
petiole and postpetiole decidedly opaque and more coarsely sculptured. The 
antennal scapes are distinctly shorter and the postpetiole is very noticeably 
smaller, more depressed dorsally, as compared with the petiole, though twice 
as broad as the latter and distinctly broader than long. Epinotal spines more 
acute. Color and pubescence much as in the typical da and the subsp. mawrz- 
tanica Forel. 
female (undescribed). Length 2—2,3 mm. 
Differing from the female of the typical form in the same characters as 
the worker; the dorsal flattening of the postpetiole even more pronounced. 
Wings like those of the typical form, hyaline and iridescent, with colorless veins. 
