THE SAXGUINARY ANTS. 4 6 7 



erable numbers appears to be the signal for another marked change in 

 the instincts of the female. She now becomes very timid, fleeing 

 whenever the nest is disturbed and taking refuge in the darkest and 

 remotest corner of the nest. In this instinct phase the female remains 

 throughout the remainder of her life. The reactions displayed in the 

 foregoing experiment are, moreover, so definite, uniform and purpose- 

 ful even in artificial nests that one can hardly doubt that they are 

 similarly manifested in a state of nature. It is evident that, especially 

 in timid, incipient, wild colonies of F. subsericea, the females may meet 

 with less opposition and therefore with greater and more immediate 

 success. " Still the fact that rubicunda is a local ant and by no means 

 one of our most abundant species shows that the successful establish- 

 ment of colonies in a state of nature must be attended with considerable 

 difficulties. The search of the rubicunda female for weak or incipient 

 subsericea colonies, even in regions where the latter ant is very abun- 

 dant, must often be vain or illusory. This is tantamount to saying that 

 the element of chance must enter very largely into the life of the rubi- 

 cunda queen, just as it does into the lives of most parasitic animals. 



If it should happen that the rubicunda queen enters a subsericea 

 nest with a queen of its own, the latter must be eliminated. In one of 

 my artificial nests there was a queen cocoon among the worker cocoons 

 of subsericea appropriated by the rubicunda. She eventually hatched 

 and lived unmolested for a time. In the course of some weeks, how- 

 ever, the subsericea workers began to pull their sister about by the 

 legs and antennae in a vicious manner. One morning, probably as a 

 result of this treatment, she was found dead in the nest. This assassi- 

 nation of a queen by her sister workers acquires a new significance in 

 the light of Santschi's observations on Wheeleriella and Mononwriuni 

 saloinonis to be described in Chapter XXVII. Perhaps in many cases 

 the subsericea queen is simply driven out of the nest or killed by the 

 intrusive rubicunda queen. Which of these two methods is commonly 

 adopted can be determined only by further observations and experi- 

 ments. It is certain, however, that queens of the slave species are not 

 permitted to live in mixed dulotic colonies of the sang nine a and Pol- 

 yergus type. In this respect these colonies resemble the mixed colonies 

 of the temporary and permanent social parasites. 



My experiments and conclusions were received with skepticism by 

 Wasmann (1906/1) and Escherich, because they had been performed on 

 unfertilized queens. These authors argued that fecundated queens in 

 their natural environment would probably behave differently. Was- 

 mann performed several experiments with such queens and found that 

 they were adopted by the slave species without hostility. Yiehmeyer, 



