071 some Carnivorous Insects. 319 



an enemy that would have made short work of them. 

 How short, is suggested by the following incident. Some 

 years ago (1902-3) three goats died under circumstances 

 that suggested meat hunger on the part of my Kaffirs. 

 Not to gratify them, I pretended to poison the carcases 

 (using only salt, however), and placed them out in a lonely 

 part of the Chirinda forest " to kill wild beasts." I might 

 have spared even the salt, for they speedily became pro- 

 tected against the most venturesome native — or " wild 

 beast " — by a dense, black, seething mass of " Idunga." 

 They remained so for only a very few days. Then the 

 ants resumed their more normal avocations, and left three 

 skeletons behind them. It sometimes happens too that 

 great stampeding is heard in the kraal or shed at night 

 amongst whatever animals are enclosed in it, and, going 

 out gun in hand, expecting perhaps to find that leopards 

 have broken in or that lions are trying to make the animals 

 break out, one finds the place full of — drivers. 



I have on one or two occasions found quantities of 

 chitinous debris — of milhpedes, grasshoppers, beetles and 

 other animals — mixed with earth in a heap outside what 

 seems to be, at any rate, as near an approach to a per- 

 manent habitation as these ants employ; and once, in 

 my garden, my foot suddenly went through and revealed 

 a hole, perhaps eighteen inches deep, which was full of 

 the driver-ants, though, it being in the dry season, it was 

 long since I had seen them about. I could hardly have 

 investigated properly without cyaniding them, and I did 

 not wish to lose the protectors of my garden ; but the 

 discovery, and the fact that on several subsequent occasions 

 I found them still there, suggested that they do possess 

 headquarters and occupy them for prolonged periods. 



It struck me early in 1911, when Dorylus was specially 

 active in the neighbourhood of my house, that it would be 

 interesting to ascertain whether any non-flying insects are 

 protected from these marauders. I accordingly carried 

 out the experiments I shall describe first. Two years 

 later I carried out the experiments with butterflies' eggs. 



I had found, in the numerous experiments on many 

 insect-enemies in which I had used adult insects as prey, 

 that not only do differences in acceptabihty exist, some 

 species being obstinately refused while other species are 

 eagerly eaten, but that the finest gradation exists between 

 those insects (Z) that are only accepted when the enemy 



