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Psyche 10:205-209, 1903.

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19031 WHKELER:- CERAPACHYS AUGUSTAE 205
SOME NOTES ON THE HABITS OF CE~APACHYS AUGUSTAE. BY WILLIAM MORTOX WHEELER, NEW YORK, N. Y. A year ago [ described in the Biological bulletin (Vol. 3, No, 5, Oct. 1902, p. 18 1-19 I) a singular Texan ant (Cer@achys [Par~~yscid\ augustae, of all known New World Formicidae the most primitive and generalized. The few specimens that furnished the types of the species were found under circumstances precluding a study of their habits. These, however, must be more thoroughly known before the precise taxonomic affinities of the tribe Cerapachyi to the Dorylinae and Po- nerinae can be determined. I was well pleased. therefore, during the past spring to happen on another larger living colony of these extremely rare ants together with their eggs, and to be able to study their behavior for several days in an artificial iiest. unfortunately, these ants, like their allies, the Ponerinae and Dorylinae in general, do not thrive so well in confinement as the more highly specialized and plastic Myrmicinae and Camponotinae. Hence my observations proved to be rather fragmentary, but 1 have seen fit, nevertheless, to record them because they shed some light on the habits and development of the Cerapachyi and thus bring us a step nearer to a determination of their natural affinities. The colony of C. augustae, on which the following observations were made, was discovered May 6th, 1903, near high water mark in the bottom of Shoal Creek at Austin, Texas. It was inhabiting a simple, straight gallery about 5 cm. long by 7 mm. in diameter, under the very center of a large block of limestone. At one end the gallery dipped down into the soil to a depth of 4 cm. The ants, 29 in number, were all congregated in the surface gallery with their long bodies wrapped about a large packet of eggs. only workers were found, though careful search was made for the peculiar wingless female described in my former paper. The whole colony, with the possible exception of a few ants that may have been out foraging, was captured and placed in a small Petri dish, tlie bottom of which had been pro- vided with a thin layer of damp soil partly covered with a glass microscope slide. The ants soon took up their abode under the slide after collecting their scattered eggs. Nymphs of two common Texan termites (Amiimes tubiformans and Euter- mes cinereus) were cut into a few pieces and given them as food. Even when these were placed only a few millimeters from the ants, the latter showed no signs of noticing them till they were actually touched with the antennae. And even then the ants often hesitated before attacking the still struggling heads and thoraces. Iiventually the termites were dispatched by the ants curling about them and using both mandibles and sting.
The latter produced sudden paralysis.
Then the ants
eagerly lapped up the juices exuding from the cut ends of the termite fragments,



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206 PSYCHE [Oct.- Dec.
while remaining very quiet as if absorbed in the delight of feeding. The mandi-
bles seemed to be too feeble to cut or puncture even so thin a chitinous invest- ment as that of the termites.
The antennae are undoubtedly the most important and remarkable organs of Cerafiachyx. This is shown by their great thickness (whence the name of the genus), the differentiation of the glancliform terminal joint of the flagellum, and their sin- gular Ireedom of movement. This freedom is permitted by the clypcus which is much compressed laterally in the form of a vertical crest, and does not overlap the scapes on the sides. The antennae are, in fact, kept in continual vibration in a plane perpendicular to the head with their elbows uppermost and not directed sick- wise as in other ants, while tlie glandiform joint of the flagellum plays over the surfaces with which it comes in contact. The insects must be guided almost exclu- sively by the contact-odor sense in these organs since they have no trace of eyes. Pronounced negative heliotaxis, evidently depending on some pliotodermatic sense. was apparent when the ants were exposed to the sun, though they did not respond very readily to the lower intensities of diffuse day-light. Strangely enough, this neg- ative heliotaxis was not associated with a high degree of positive thigmotaxis, as it is in many other insects, since the animals showed no decided tendency to con- ceal themselves with their bodies applied to the earth or glass. Often the whole colony would lie exposed for hours on the surface of the soil, meiely aggloiri- eratecl in a mass about their eggs.
As the number of eggs visibly increased during tlie confinement of the colony, it is clear that some of these must have been laid by the workers, as there was no female in the nest. No ants conld be more careful of their eggs. They enveloped them with their bodies so that the packet could not be seen except by clistui-b- ing the whole colony. When the packet was broken apart the eggs were eagerly sought and deftly brought together again. This brooding over the eggs is quite unlike anything I have seen in other ants except Eciton, the smaller species of which (E. opac///;orax, schmifti, siim/chrasfi, etc.) have a very similar habit. Besides affording protection to the eggs, it may, perhaps, serve to hasten the embryonic development.
The eggs are very slender (Figure, a),
being fully four times as long as broad. They are not kept in several packets
with the long axis of the component eggs parallel with one another, as in some



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Ponerinae (Lcptogenys, Piichycondyla), but without any definite orientation in a single su11sphe1-ical mass. The first eggs did not hatch till May 14tl1, showing that the incubation period must exceed eight days. They hatched rather slowly, a few at a time.
The larvae (Figure, 6) were extremely slender, not twice as broad behind as at the anterior end, with well-marked segmental constrictions. The head is pro- portionately large, with strong, acute mandibles projecting- beyond the clypeal and labial regions. The maxillae are furnished with a pair of prominent sensory papillae and the labium with a well-developed duct to the spinning glands. The dorsal surface of the head as well as the whole surface of the body is covered uni- formly with short, slightly curved hairs. There are no traces of tubercles of any description. Attempts to observe the method employed by the ants in feeding their larvae were unsuccessful. Once, on placing a number of eggs and young larvae of Camponotus festinatus in the nest, I saw the young Cerapachys larvae feeding on the former after they had been carried under the slide by .the workers. It was apparent also that the ants and their older larvae soon began to feed on the unhatched eggs and younger larvae of their ow11 species, for the number of progeny decreased rapidly from day to day. In order to reduce the size of the colony and thus save as many o[ the young as possible from destruction, I killed and removed twelve of the workers May 17th. 1 was not successful, however, in stopping the infanticides, so on the following day 1 removed six more workers. By this time, however, though I had provided the nest daily with fresh termite food (the ants would not eat sweets, larvae of other ants, or miscellaneous insects) the Cerapachys became so demoralized that by May 19th no eggs and only five half-grown larvae remained. These larvae were carried by the ants after the manner of Eciton and Leptogenys, i. e. by the neck, with the long slender body extending back between the legs of the worker. The ants were quite as careful of their larvae as of their eggs.
To my intense cliscippointment, it soon became manifest that I should be unable to rear the few remaining larvae to the pupal stage. I therefore killed the surviving workers and the three lanvc still uneaten May 20th. Thus I was unable to settle two important questions : first, the method of feeding the larvae, whcther by regurgitation or with pieces of insect food; and, second, the character or the pupa, whether naked or covered with a cocoon. The powerful development of the larval jaws would seem to indicate that the young are fed with pieces of insect food, and from the tact that the laival spinning glands'seem to be well developed, one may infer that the pupa is cncloscd in a cocoon. Whoever is so fortunate as to happen on a colony ol these ants during the middle or latter part of June will probably be able to determine the pupal characters without difficulty, as the pupae should at that time be found in the nests.



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208 PSYCHE [~ct.- ~ec.
What light do these few observations, together with those recorded in my pre- vious paper, shed on the affinities of the Cerapachyi to the Ponerinae on the one hand and the Dorylinae on the other? It is clear that the following trails of C. augitstae are decidedly Ponerine :-
I. This ant lives in small colonies like the Ponerinae (Stigmatomma, Ponera, etc.) and not in pop~tlous 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. uz~gustae 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.1
4. C. aupustae 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, i. 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, ctc.) .
A fine colony of Ecifon sckmiffi which I kept a few years ago, exhibited this restlessness in a striking and ludi- c manner. The colony was at first confined in a tall glass jar on a sqmi-re board surrounded by ;i water moat. TIE
ants kept ping up and down the inside of the jar'in files for many houis. 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 rill it met the column at the tnmingpoint. To my su~prisc it kept right on over lhe same circwnference d~icl~ was long enough to accotnnmdate the whole colony. The ants contin- uedgoing round andround the circular base of the jar, following one another like so many sheep, without the slightest inkling that they were perpetually traversing the same path. They behaved exactly as they do on one uf their predatory expeditions. They kept up lhis gyration roi- 46 Ihuurs belore the column broke and spread over the hoard to the water's edge and clustered in the manner so characteristic of this and the allied species (E. opacifhwax, sumichrasii, etc.). I have never seen a more astonishing exhibition of the limitations ( gemanice " Bornirthcit") of instinct. For nearly two whole days tlieae blind creatures, so dependent on the contacl-odor sense of their antennae, kept palpitating their uniformly smooth, odoriferous trail and the a-dvanciiip- bodies of the ants immediately preceding them, without perceiving' that they were making no progress bnt only wasting their energy, till the spell was finally broken by some more ventwc- some memlxrs of the colony, Recently I have found a renmrk~~ble observalion of the same kind recorded by Fabre in the 6th volume of his incompaiable "Souvenirs Entotnolofiiqaea." He desciibes an army of caterpillars of the " proms- ionnaire 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 S-iliours altogether, slopping to rest on their path only when overtaken by the cold, and not actually deviating till the eighth day. Fabre estimated that the caterpillars. wled around the vase 333 times! In this case the insects were not guided by contact-odor like the Ecitons, but by the dkeu thread spun by each individual over the surface traversed.



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8. The eggs are shaped like those of certain Ponerinae (Leptogenys, Pachy- condyla).
9. The larva probably spins a cocoon.
On the other hand C. augustae exhibits unmistakable Doryline characters : - I.
In the conformation of the head and antennae which closely resemble those of Eciton.
a. In the habit of brooding over the eggs. The following characters are common to both Dorylinae and Ponerinae : - I
The method of carrying the larvae is common to forms like Eciton and Leptogenys,
a.
The larva is intermediate between that of Eciton and Stigmatomma. It is covered with shorter, less flexuous, and less abundant hairs than the latter and in these particulars resembles the larvae of Eciton.1 These facts go to show that C. aufusfae is a generalized form much like the hypothetical ancestor from which both Dorylinae and Ponerinac are supposed to have sprung. At the same time, the majority of the characters are Ponerine and justify us in adopting the views of Forel who places the tribe Ccrapachyi with the Ponerinae. Other species of Cerapachys bear out this interpretation. Dr. Hans Brauns writes me from Willowmore, Cape Colony: "Cerapachys ist doch wohl sicher eine Poneridc. C.peringuej~i ist bei Port Elizabeth keineswegs selten, hier einzeln. Ihr ganzes Betragen ist das eirier Poneride." Owing to the close relationship of Cerapachys with both Ponerinae and Dorylinae, the recent discovery by Emery of a form (Aneuretus) intermediate between the Ponerinac and the Dolichoderinae, and the patent relationship between the Ponerinae on the one hand and thc Myrmicinae and Camponotinae on the other, it is evident that the Formicidae constitute a very compact group of Hymenoptera. This unitary character of the group is still further emphasized by its comparatively recent geological origin. Hcnce it should be designated as a family, and its five divisions as subfamilies, in accordance with the views of Euro- pean myrmecologists like Emery, Ford, Mayr, Wasmann, etc.; and the recent tendency of some Cisatlantic 11ymenopte1-ists to regard the ants as a superfamily Formicoidea "), consisting of the five families Myrmicidae, Poneridae, etc., is not to be commended merely for the sake of making the nomenclature of this group look like that of some of the other divisions of the Hymenoptera. 1 I have not seen Emery's description of the larva of the Ponerim Ectatorama, but I have been able to examine the larvae of E. (Halcoponera) sfn'gatum Norton from Guadalajara. Mexico. Thcse larvae are noiituberculate like those of SiignzdomwafS!22>m (Bid bull., ~po, vol. 2, p, &i, fig. 8) but covered with long, muhifurcate, somewhat flexuous hairs. An exhaustive monographic study of ant-larvae would ceitiiinly iepay the investigator, as they present a bewildering array of interesting characters in the various tubercles, " poils d'accrochage, " ctc., with which they are provided.



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