Wasps, Bees, and Ants 547 



which the amber honey shines. The honey is obtained by the workers 

 from fresh (growing) Cynipid galls on oak-trees, which exude a sweetish 

 sticky liquid which is brought in by the foraging workers and fed to the 

 sedentary honey-holders by regurgitation. It is held in the crop of the 

 honey-bearer, the distention of which produces the great dilation* of the 

 abdomen. The stored honey is fed on demand to the other workers by 

 regurgitation; a large drop of honey issues from the mouth of the honey- 

 bearer, resting on the palpi and lips, and is eagerly lapped up by the feeding 

 individuals, two or three often feeding together. A somewhat similar honey- 

 ant, Prenolepis imparis (Fig. 750), is common in California. 



The most interesting, however, of the familiar American ants are the 

 "slave-makers" and their "slaves." Three species of slave-makers occur 

 in North America, of which two belong to the family under present discussion. 

 These are Formica sanguinea, represented by five subspecies, and Polyergus 

 rufescens, the shining slave-maker, represented by two subspecies. The 

 third slave-making species, Tomognathus americanus, is a rare Myrmicid. 

 The slaves of F. sanguinea are other smaller species of the same genus, espe- 

 cially F. subsericea, F. nitidiventris , and F. subcenescens, while the slaves of 

 Polyergus are the same species of Formica and the additional one, particu- 

 larly common as a slave form, F. schaufussi. Communities of the slave- 

 making species are occasionally found in which there are no slaves; when 

 slaves are present they may be few or many; usually they are more numerous, 

 proportionally, the smaller the numbers of the slave-makers in any com- 

 munity. The slaves are captured by the attack, by a body of slave-making 

 workers, on a slave-ant community and of the pillage of the attacked nest of 

 larvae and pupae; some of these may be eaten, but others are brought back 

 unharmed to the slave-makers' nest. Here more yet may be eaten, but most 

 are cared for and soon hatch to become the slaves of their captors. Never 

 are adults enslaved; they are killed or driven off during the attack. The 

 slaves undertake unhesitatingly all the varied work of bringing in food, nest- 

 building, and caring for the young in the community. Indeed in some cases 

 the slave-makers come to be very dependent on the slaves, which ought really 

 then to be called auxiliaries or helpers, for the slave-maker workers also 

 assist in all the community undertakings, while the "slaves" often seem 

 to dominate, or at least to be quite as important as, their would-be rulers in 

 the determination of the course of events in the compound community. So 

 far does this dependence go in the case of certain foreign ants that the origi- 

 nally dominant species loses its workers, and is thus absolutely dependent 

 on the auxiliary species for the maintenance of the community. In the 

 general division of labor in the compound community the fighting is always 

 done, at any rate chiefly, by the slave-makers. McCook has described in 

 some detail the community life of the shining slave-maker, Polyergus lucidus, 



