THE COMPOUND NESTS. 4 3 7 



Poyonoin\nne.\-. It is possible, however, as I have suggested ( 1901^), 

 that both Dor \in\nne.\- and Forellus merely nest in the Poffonomyrmex 

 clearings because they prefer barren, sunny spots. 



D. Lestobiosis. Forel (igoib) has given this name to an extensive 

 group of forms, the " thief ants," which I formerly included under 

 cleptobiosis. At least the workers of these ants are of very small size 

 and nest in the earthen walls separating the roomy galleries and cham- 

 bers of termites and other larger ants. The lestobiotic species, most 

 of which belong to the Myrmicine tribe Solenopsidii, comprise the 

 following : 



1. Phe-idolc ealens, a small granivorous ant which nests on the 

 mounds of Pogonomyrmex barbatus in Mexico, and probably helps 

 itself to the seeds stored up by this ant in the flat, superficial chambers 

 of its nest. 



2. Solenopsis fuga.r of Europe, the African S. orbula and latro, the 

 North American S. molesta and te.vana, and probably also many of the 

 South American members of the genus. The workers of these ants are 

 all very small and yellow, with vestigial eyes and are decidedly hypogseic 

 in their habits. They often, but by no means always, live in the gallery 

 walls of other and much larger ants. When this is the case, the pas- 

 sages occupied by the Solenopsis communicate with the apartments of 

 the other species and are too tenuous to admit the workers of the latter. 

 These do not appear to notice the little thieves which move about freely 

 in the galleries and chambers and kill and eat their helpless larvae and 

 pupae, as Forel (1869, 1874), Wasmann (1891/0, and especially Janet 

 ( 1897?), have observed in S. fuga.r. Our American molesta has very 

 similar habits, but is often found leading an independent existence. It 

 is also sometimes a pest in kitchens and is known to eat dead insects 

 and the sprouting kernels of maize (Forbes). 



$. Diploiiioriiini longipenne. Workers of this ant, which are small 

 and yellow like those of Solenopsis, were sent me by Dr. Hans Brauns, 

 who took them in Cape Colony in nests of a pale variety of Messor 

 barbarus. These specimens were labelled " thief ants," and probably 

 lived with the Messor in the same manner as Solenopsis lives with 

 species of Formica and other genera. 



4. Carebara vidna, liynata, etc. These ants, which occur only in 

 the African and Oriental regions, have minute, yellow, small-eyed 

 workers like Solenopsis, but their males and females are gigantic and 

 dark-colored, and have well-developed eyes and ocelli (Fig. 256). 

 Carebara ridua was found by Haviland (Forel, 1901) nesting in the 

 hills of Tcrmcs natalensis. There can be little doubt that the workers 

 feed on the termites or their young and on account of their diminutive 



