2o8 PSYCHE [Oct.— Dec. 



What light]clo these few observations, together with those recorded in my pre- 

 vious paper, shed on the affinities of the Cerapachyi to the Ponerinae on tlie one 

 hand and the Doryhnae on the other ? It is clear that the following traits of C. 

 augiistae are decidedly Ponerine : — 



1. This ant lives in small colonies like the Ponerinae (Stigmatomma, Ponera, 

 etc.) and not in populous colonies like the Dorylinae. 



2. Its nest has a very simple structure like that of the Ponerinae. 



3. The colonies are stationary like the Ponerinae and not nomadic like the 

 Dorylinae. In confinement, at least, C. augustac made no attempts to leave the 

 nest and showed none of the singular restlessness which characterizes confined 

 colonies of Eciton, but behaved like the home-loving species of Ponera, Lep- 

 togenys, Pachycondyla, etc.i 



4. C. augiistae exhibits the same slow, monotonous, and timid behavior as the 

 Ponerinae (Stigmatomma e. g.) in marked contrast to the intrepid, predatory 

 instincts of the Dorylinae. 



5. The female of the Texan Cerapachys is not dichthadiiform, /. e. shaped like 

 the huge wingless females of Dorylus and Eciton, but resembles the workers in 

 form and stature. Some species of Cerapachys are known to have winged females. 



6. The workers are all very nearly of the same size and structure and in these 

 respects resemble the workers of the Ponerinae. There is no tendency to poly- 

 morphism as in Dorylus and Eciton. 



7. The petiole and post-petiole resemble the corresponding parts of certain 

 Ponerinae (Stigmatomma, etc.). 



* A fine colony of Eciton schtnitti whicli I kept a few years ago, exhibited this restlessness in a striking and ludi- 

 crous manner. The colony was at first confined in a tall glass jar on a square board surrounded by a water moat. The 

 ants kept going up and down the inside of the jar in files for many hours. Finally I removed the lid. The file at once 

 advanced over the rim and descended on the outer surface till it reached the circular base of the jar where it turned to the 

 left at a right angle and proceeded completely around the base till it met the column at the turning point. To my surprise 

 it kept right on over the same circumference which was long enough to accommodate the whole colony. The ants contin- 

 ued going round and round the circular base of the jar, following one another like so many sheep, without the slightest 

 inkling that they were perpetually traversing the sarne path. They behaved exactly as they do on one of their predatory 

 expeditions. They kept up this gyration for 46 hours before the column broke and spread over the board to the water's 

 edge and clustered in the manner so characteristic of this and the allied species {E. opacithorax, sumichrasti, etc.). I 

 have never seen a more astonishing exhibition of the limitations ( ^^r;«««/ifs " Bornirtheit ") of instinct. For nearly 

 two whole days these blind creatures, so dependent on the contact-odor sense of their antennae, kept palpitating their 

 uniformly smooth, odoriferous trail and the advancing bodies of the ants immediately preceding them, without perceiving 

 that they were making no progress but only wasting their energy, till the spell was finally broken by some more venture- 

 some members of the colony. Recently 1 have found a remarkable observation of the same kind recorded by Fabre in 

 the 6th volume of his incomparable " Souvenirs Entomologiques." He describes an army of caterpillars of the " proces- 

 sionnaire du pin" (Cnethocampa pityocampa) going round and round the outside of a large vase 1.35 m. in circumference 

 for seven days ! During this period the caterpillars were on the march 84 hours altogether, stopping to rest on their path 

 only when overtaken by the cold, and not actually deviating till the eighth day. Fabre estimated that the caterpillars 

 crawled around the vase 335 times ! In this case the insects were not guided by contact-odor like the Ecitons, but by the 

 silken thread spun by each individual over the surface traversed. 



