THE SANGUINARY ANTS. 



461 



etc. These forms are enslaved only when sanguined happens to be 

 living in the particular regions where they are the dominant fusca 

 forms. But as these regions are usually inhabited by subscricea to 

 some extent, this ant never enjoys complete immunity if there are any 

 slave-makers in the neighborhood. Occasionally sanguined colonies 

 are found to contain slaves of two or even three fusca or pallid c-fulru 

 forms. One small colony observed at the edge of a meadow in Colo- 

 rado contained neoclara, ncocinerea and nitidii'cntris workers in nearly 

 equal proportions. 



According to my observations, our sanguinca makes many more raids 

 during the course of the summer than her European prototype. On 



FIG. 269. Dealated females, workers, larvae, nude and covered pupae of Formica 

 snbsericea. nearly twice the natural size. (Photograph by J. G. Hubbard and Dr. O. 

 S. Strong.) 



several occasions I have seen a colony plunder a subscricca nest nearly 

 every day for a week or a fortnight. Provided Forel's statement in 

 regard to the typical sanguinca is correct, this peculiarity of the Amer- 

 ican forms would account for its having so many more slaves. This, 

 however, is not the only reason : though individually smaller as a rule, 

 less pugnacious and living in smaller and obscurer formicaries, our 

 sanguinca enslaves fusca forms which are much more cowardly and 



