4 o THE POPULAR SCIENCE MONTHLY. 



account in the so-called " oyster-schools " of France. The distance 

 from the coast to Paris being too great for the newly-dredged oysters 

 to travel without opening their shells, they are first taught in the 

 schools to bear a longer and longer exposure to the air without gaping, 

 and when their education in this respect is completed, they are sent on 

 their journey to the metropolis, where they arrive with closed shells 

 and in a healthy condition. 



The social life of ants has many parallels to that of the barbarous 

 races of human beings. Thus, the habit of making slaves is said to 

 obtain among at least three species of ant. A community attacks a 

 nest of another species in a body ; there is a great fight with much 

 slaughter, and, if victorious, the slave-makers carry off the pupae of 

 the vanquished nest in order to hatch them out as slaves. When the 

 pupae hatch out in the nest of their captors, the young slaves begin 

 their life of work, and seem to regard their masters' home as their 

 own ; for they never attempt to escape, and they fight no less keenly 

 than their masters in defense of the nest. In the nests of Formica 

 sanguinea the comparatively few captives are kept as household slaves. 

 They never leave the nest, and so all the out-door work of foraging, 

 slave-capturing, etc., is performed by the masters. 



F. rufescens, on the other hand, assigns a much larger share of 

 labor to the slaves. In this species the males and fertile females do 

 no work of any kind, and the workers, or sterile females, though most 

 energetic in capturing slaves, do no other kind of work. Therefore 

 the whole community is absolutely dependent upon its slaves. Huber 

 shut up thirty masters without a slave and with abundance of their 

 favorite food, and also with their own larva? and pupae as a stimulus 

 to work ; but they could not feed even themselves, and many died of 

 hunger. He then introduced a single slave, and she at once set to 

 work, fed the surviving masters, attended to the larvae, and made some 

 cells. 



A predatory expedition of ants for capturing slaves, or robbing the 

 storehouse of another nest, marches out in a close column numbering 

 from a few hundreds to several thousands. The army is guided to its 

 destination, which may be an hour's march distant, by several ants 

 who run from side to side with heads down, evidently finding their 

 way by scent. A marauding excursion of the F. rufescens, or Ama- 

 zons, against the F. rufibarbis, a sub-species of the F.fusca, or small 

 black ants, took place as follows : The vanguard of the robber army 

 found that it had reached the neighborhood of the hostile nest more 

 quickly than it had expected ; for it halted suddenly and decidedly, 

 and sent a number of messengers which brought up the main body 

 and the rear-guard with incredible speed. In less than thirty seconds 

 the whole army had closed up, and hurled itself in a mass on the dome 

 of the hostile nest. This was the more necessary, as the rvfibarbes 

 during the short halt had discovered the approach of the enemy, and 



