THE AMAZONS. 473 



of 1904 contained only rufibarbis slaves, but during 1907 contained 

 only glebaria. 



Unlike sanguined, rufcsccns makes many expeditions during July and 

 August, but these expeditions are made only during the afternoon hours. 

 One colony observed by Forel (1874) made 44 sorties on thirty after- 

 noons between June 29 and August 18. It undoubtedly made many 

 more which were not observed, as Forel was unable to visit the colony 

 daily. He gives the following statistics on these 44 expeditions : " On 

 4 of them the army separated into two columns, from 6 it returned 

 without having found a nest to plunder (through fatigue or losing the 

 trail), on 3 the amazons found only formicaries containing neither 

 larvas nor cocoons, from 6 they brought back only a meager supply of 

 these, from 25 a great number. Of the 44 attacks, 19 were on fusca 

 colonies and 19 on rufibarbis. Three of the latter were unsuccessful 

 because they yielded no booty. The same formicary was visited repeat- 

 edly: the ants visited altogether 7 colonies of fusca (one 6 times, one 

 4 times, one 3 times, two twice and two once ), and 8 rufibarbis colonies 

 (one 5 times, two 4 times, one twice and four once )." Forel estimated 

 the number of amazons in the colony at more than 1,000 and the t,otal 

 number of pupse captured at 29,300 (14,000 fusca, 13,000 rufibarbis 

 and 2,300 of unknown provenience, but probably fusca}. The total 

 number for the summer ( 1873) was estimated at 40,000. This number 

 is certainly above the average, as the amazon colony was an unusually 

 large one. Colonies with only 300 to 500 amazons are more frequent, 

 but a third or half of the above number of pillaged cocoons shows what 

 an influence the presence of a few colonies of these ants must have on 

 the Formica colonies of their neighborhood. Of course, only a small 

 proportion of the cocoons are reared. Many of them are undoubtedly 

 injured by the sharp mandibles of the amazons and many are destroyed 

 and eaten after they have been brought home. 



The tactics of Polycrgns, as I have said, are very different from 

 those of sanguined. The ants leave the nest very suddenly and assemble 

 about the entrance if they are not, as sometimes happens, pulled back 

 and restrained by their slaves. Then they move out in a compact 

 column with feverish haste, sometimes, according to Forel, at the rate 

 of a meter in 33^ seconds or 3 cm. per second. On reaching the nest 

 to be pillaged, they do not hesitate like sanguined but pour into it at 

 once in a body, seize the brood, rush out again and make for home. 

 When attacked by the slave species they pierce the heads or thoraces 

 of their opponents and often kill them in considerable numbers. The 

 return to the nest with the booty is usually made more leisurely and in 

 less serried ranks. 



