APHIS HERDS AND ANT ASSOCIATES 



and in forming its compound nest it shows a strong pur- 

 pose to keep its own living-quarters quite distinct from 

 its associates, although the workers mingle freely with 

 the Myrmicas in their larger galleries. As compared 

 with these, the gangways of Leptothorax are small, and 

 evidently are so made and kept to maintain their isola- 

 tion and hold their robust neighbors at a distance. It 

 is only by a deliberate onset of sappers and miners that 

 the larger ants can make way through their dwarfish 

 associates' narrow lanes; and this is occasionally done ; 

 although for the most part the Myrmicas seem content 

 to let the Leptothorax alone. 



A sectional view of the joint underground commune of 

 the two species shows the parts occupied by Leptothorax 

 quite apart from Myrmica, but united thereto by their 

 narrow alleys. The " China town," or foreign quarters 

 of some of our cities, might be suggested, not inaptly, 

 as a somewhat analogous communal subdivision on 

 racial lines. 



In spite of this maintenance of independent quarters 

 for themselves and their offspring, the two species are 

 truly symbiotic. They intermingle on the most amicable 

 terms; they run about together in the main galleries 

 and large myrmican chambers; and they exhibit, under 

 favorable circumstances, the chief bond of union that 

 holds this strange compound commune together; it is 

 the old, old " bread-and-butter" bond that draws to- 

 gether communities of men. The Leptothorax under 

 normal conditions obtain their food from the Myrmicas, 

 and from them alone. [W. 4, p. 14.] 



A peep through the glass roof of an artificial nest 

 shows a Myrmica worker standing stock-still in a gallery 

 with a Leptothorax mounted upon its back. What does 



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