ALIEN ASSOCIATES AND AFFINITIES 



First, with sluggish movements, slowly stirring; then 

 more vigorously, as the sunshine fell upon the branches; 

 until by nine o'clock the tree-paths were thronged with 

 workers, most of them repletes, and homeward bound. 

 So also it was on the mounds. As the sunlight pierced 

 the woods, and fell upon them and warmed them up, 

 they resumed their normal activity. The benumbing 

 effect of the frost upon the insects had been no doubt 

 intensified by its suddenness, and the high temperature 

 that had preceded it. 



The above facts led me to studies of the winter condi- 

 tion of the mound-makers, which were made late in 

 October, 1876, and the latter part of February, 1877. 

 [McC. 2, p. 286.] It was found that the winter tended 

 to drive alien insects to the formicaries for harborage. 

 Lodged in one nest was found a colony of our native 

 termites. They were in an unfrozen part, exposed to 

 the sun, occupied a space of about four inches square, 

 and were then (February 14th) quite lively. Near them 

 was a large herd of roaches, a hundred or more. The 

 ants in the mound were not torpid, although their 

 characteristic vigor and activity were suspended. It 

 would not have been possible for the termites to hold 

 such a position in midsummer; they would have been 

 eaten. Such a cluster of cockroaches would have been 

 equally impossible; it would have been scattered and 

 destroyed. This is doubtless the general experience. 

 Wheeler [W. 1, p. 30] found that in Texas, during 

 autumn and winter, the nests of Formica gnava teem 

 with alien insect guests of various orders, larvae and 

 adult, that are rarelv seen in summer. 



\, 



How shall we account for this? In the case of the 

 mound-making ants, there seem to be two factors, one 



227 



