244 



PSYCHE. 



[September, 1901 



materials. I placed a handful of exsec- 

 tollies from a nest in a wood, about five 

 hundred paces from another, toward the 

 latter, in order to discover if they were 

 of the same colony. Some workers 

 seized the newcomers for an instant by 

 the legs. Aside from this, peace and 

 fusion. The experiment is not, however, 

 conclusive, because in Europe we see 

 F. exsecta of differejit colonies behave in 

 nearly the same manner. 



By making some F. cxscctoides fight 

 with other species {pallidefulva and 

 sanguined)., I was able to ascertain that 

 they have not, like exsecta of Europe, 

 the instinct to seize their enemies by the 

 neck, in order to saw it apart. Their 

 analogy with their European congener is, 

 therefore, only partial. 



At Cromwell, in the brush of a cleated 

 woodlot, I had the good fortune to be 

 present at the attack on a formicary of 

 huge F. subscricea by a feeble band oi F. 

 sirnguinca, smaller and much less numer- 

 ous. The sanguinca were scarcely thirty 

 in number and a third of them were re- 

 cently enclosed workers, still immature. 



Evidently it was a newly started form- 

 icary which was thus engaged. The 

 subsericca had their nest at the foot of a 

 large mullein (Verbascum). In number 

 they were at least tenfold their aggress- 

 ors. Each of them was, I can affirm, as 

 well armed and on an average larger 

 than and equally as robust as any of the 

 assailants. Well, the mere arrival of 

 this little troop of sangiirnea was suffi- 

 cient to spread a panic in the formicary 

 of subsericca which fled with their larvae 



and pupae without attempting any seri- 

 ous defense, allowing the sanguinca to 

 seize their young and take possession of 

 their nest. Only one or two small sati- 

 guinca were killed. The instance is note- 

 worthy because in this case neither the 

 formidable weapons, the violence, nor 

 the impetuosity of the little band of 

 Polyergus ru/escens whose similar aggres- 

 sions I have described in my " Fourmis 

 de la Suisse " can be alleged. The bold 

 and courageous tactics of the sanguinca 

 were even somewhat less marked than 

 among those of Europe, which fight with 

 species smaller and weaker than them- 

 selves. I have never seen a cowardice 

 so absurd or so complete as that of these 

 American subsericca, and this cowardice 

 indicates very clearly the instinctive 

 adaptation of the slave-making species to 

 attack and of the enslaved species to flee. 

 At Hartford, Ct., I discovered a small 

 mixed formicary of Formica cxscctoides 

 and F. subsericca. There was scarcely 

 any doubt of the common and intimate 

 life of the two species in the same nest. 

 They went in and out at the same doors, 

 etc. Here the artificial experiments of 

 a myrmecologist were excluded. This 

 case is undoubtedly the same as that de- 

 scribed for the first time in my " Fourmis 

 de la Suisse," that is to say, an abnor- 

 mal, mixed, natural formicary resulting 

 from a battle between the two species, 

 a battle in which cxscctoides had the best 

 of it and had raised the pupae taken 

 from subsericca. Here, as in Switzer- 

 land, the mixed formicary was not popu- 

 lous, much less so than those of exsectoides 



