ANTS AND THEIR GUESTS WASMANN. 469 



of prey and therefore are mostly restless wandering ants. They are 

 the scourge of the host of lesser animal hfe in the tropics. They 

 lack composite (reticulate) eyes; in their place there are simple 

 ocelh, which, however, are frequently rudimentary or disappear 

 altogether. When these are well developed, as for example in 

 Eciton Burchelli, they can even distinguish colors, as follows from 

 the comparison of the coloration of their guests.^ Nevertheless the 

 dorylines, on account of their raids, depend upon touch and smell to 

 a still higher degree than the other ants. Most of the Eciton of the 

 Neoti'opical region, legionary ants, undertake their hunting expedi- 

 tions, already mentioned by Rengger, Belt, and Bates, in great armies 

 above ground ; Hkewise the Anomma of Africa, already observed by 

 Smeathman, which carry on their hunting drives for all small animals 

 in frequently gigantic armies, on which account they have been given 

 the name "driver ants." Anomma is a subgenus of Dorylus, the 

 species of which, on account of carrying on their hunts above ground, 

 are mostly dark colored, but whose pale colored allies (Dorylus, sensu 

 stricto), as well as those of the genus vEnictus, hunt subterraneanly. 

 The trimorphism of the worker f onn of Anomma Wilverthi is to be seen 

 from figure 23. To be sure it is connected by intermediate fonns. The 

 smallest worker form, on account of the reduced number of antennal 

 joints, might be taken, if one found it alone, for a different genus. 

 As well with Anomma as with Eciton two kinds of armies are to be dis- 

 tinguished, foraging armies and emigrating armies. Only with the 

 latter are the gigantic, entirely wingless females and the likewise very 

 large, often de-alated males carried along; with Anomma they are 

 transported across open expanses only within covered tunnels. In 

 emigrating to a new hunting region a new nest is occupied (Vosseler 

 in East Africa and Luja on the lower Congo), which for weeks serves 

 as a base for the foraging expeditions. That these nests contain 

 a fauna of guests,^ principally beetles, which live from the prey of 

 their hosts, can estrange but little. But that these ants are accom- 

 panied on their hunting expeditions by a host of guests, particularly 

 of the family of short-winged beetles (Staphyhnidae), is the more re- 

 markable, as one would suppose that the hunters would at the start 

 seize upon this readily available game. And yet the Eciton of Amer- 

 ica as well as the Anomma-Dorylus of Africa possess the largest 

 number of guests of all tropical ants! 



The theory of descent to some extent explains this riddle. The 

 greater the necessity for adaptation in relation to a certain enemy is, 

 the greater will also be — supposing the capabiUty for adaptation, 



' Die psychischen Fahigkeiten der Ameiscn, 2 ed., 1909, Chapter VI. 



' The guests of the nest of Anomma Wilverlhi, which E. Luja has found in several nests near Konduei 

 are still to be described. 



85360°— SM 1912 31 



