NA TURE 



501 



THURSDAY, SEPTEMBER 25, 1S79 



THE AGRICULTURAL ANTS OF TEXAS 



The Natural History of the AgricuUtiral Ant of Texas : 

 a M onograph of the Habits, Architectiire, and Struc- 

 ture of " Pogonoinyrmex barbatus." By Henry Chris- 

 topher McCook. Author's Edition. Academy of 

 Natural Sciences of Philadelphia. 1879. (London: 

 Triibner and Co. ) 



THE agricultural ant of Te.xas was first introduced to 

 the English public in 1862, by means of a com- 

 munication from Dr. Gideon Lincecum to Mr. Darwin, 

 published in the Journal of the Linnean Society of 

 London, and much interest ■was excited by the account 

 given of an insect which actually sowed seed, tended the 

 crop, and reaped the harvest. No further information 

 being forthcoming, doubts were expressed both here and 

 in America as to the accuracy of the observations, and 

 Mr. McCook went to Texas in the summer of 1877 for 

 the express purpose of testing them. Unfortunately, 

 however, he could only stay about three weeks, which he 

 devoted entirely to observation of the ants. He however 

 obtained information from residents, and carried away 

 some living ants on which to make further observations 

 at home, and the result is given in much detail in a 

 handsome volume of over 200 pages, illustrated by a 

 series of twenty-four plates, giving details of the nests, 

 the attitudes, the habits, the external structure and 

 internal anatomy of the species in question, and some of 

 it? allies. 



With all this elaboration, however, the main point still 

 remains in doubt, and Mr. McCook does not and cannot 

 tell us whether the agricultural ants really do sow the 

 seed, though they undoubtedly reap the harvest. What 

 he does tell us, however, is sufficiently curious. The 

 insect is a true harvesting-ant, like those so well described 

 by Mr. Moggridge, but it differs from all other species in 

 forming large cleared disks on the site of its nests. These 

 diiks vary from two to twelve or fourteen feet in diameter, 

 and are approximately circular, and however thick may 

 be the grassy or weedy vegetation around them the disks 

 are perfectly bare and smooth and thus form very con- 

 spicuous objects in the landscape. The openings to the 

 nests and granaries are near the centre of the disk, and 

 in some cases are formed in a central convex or conical 

 mound, while in others the surface is entirely flat. In 

 about one-third of the nests examined by Mr. McCook, 

 the outer border of the disk, sometimes for two feet wide, 

 was covered by a crop of ant-rice (Aristida oligantha) 

 differing wholly in appearance and colour from the sur- 

 rounding vegetation, just as a crop of wheat or oats differs 

 from a field of mixed herbage, while not a solitary weed 

 of any kind was to be found in the belt of ant-rice. 



Lincecum had stated that the seeds of the ant-rice were 

 regularly sowed in the autumn, kept weeded during winter 

 and spring, and reaped in summer. Mr. McCook was 

 only able to see the last stage. The plant had certainly 

 been weeded ; its seeds were found in the granaries mixed 

 with many others; and, it is admitted "that there is 

 nothing unreasonable, or beyond the probable capacity of 

 the emmet intellect, in the supposition that the crop is 

 Vol. XX.— No. S'7 



actually sown. Simply it is the Scotch verdict — not 

 proven." This is very unsatisfactory, and as the journey 

 appears to have been undertaken for the express purpose 

 of testing this, the only incredible part of Lincecum' s 

 observations, it seems curious that it should have been 

 made in July, at the time of the harvest, instead of in 

 November, the time of the alleged sowing of the crop. If 

 we reject the "sowing" as too improbable, the only other 

 explanation of the facts seems to be that the Aristida 

 is one of those singular plants which constantly appear 

 on cleared ground although not growing in the immediate 

 vicinity, and that the ant's clearings prepare the condi- 

 tions for its growth. A few experiments would soon test 

 this, and it is a great pity some resident could not be 

 found to determine this most interesting point either by 

 observation or experiment. The book is, however, full 

 of valuable matter as to the habits and actions and the 

 whole domestic economy of ants ; and there is a useful 

 chapter on " the ancient belief in harvesting ants — how 

 it was discredited and how restored," in which the 

 opinions of many ancient and modern authors are given 

 with a number of suggestive extracts from the classics as 

 well as from the Rabbinical laws and traditions. We 

 cannot, however, but feel some regret that the author did 

 not make more extended observations before writing so 

 voluminous a work, so that he might have been able to 

 clear up the numerous points now left in uncertainty. 

 The chief authority for a number of important statements 

 is still Dr. Lincecum, who appears to have resided for 

 many years in Texas and to have assiduously studied the 

 habits of the ants, and there does not seem to be any 

 essential point in which Mr. McCook's own observations 

 show his predecessor to have been in error. On the con- 

 trary he must be considered to have proved the substantial 

 accuracy of the doctor's facts so far as he was able to do 

 so in the limited time at his command. 



Alfred R. Wallace 



EXPERIMENTAL GEOLOGY 



Etudes Synthetiques de GMogie Experimentale. Par A. 

 Daubr^e, Membre de I'lnstitut, Directeur de l':6cole 

 Nationale des Mines, &c. (Paris : Dunod.) 



MONSIEUR DAUBR^E has, during the last thirty 

 years, published numerous very important memoirg 

 describing the production, upon a small scale in the 

 laboratory, of various natural geological phenomena. 

 These papers, which were originally scattered through 

 the pages of different scientific journals, are now for the 

 first tin:e brought together. The first part of this work, 

 under the title of " Application of Experimental Methods 

 to the Study of Various Geological Phenomena," forms a 

 handsome and well-illustrated volume of nearly five hun. 

 dred pages. This is to be followed by a second part, to 

 be entitled "Application of Experimental Methods to 

 Various Cosmological Phenomena," which will describe 

 investigations recently made on the constitution and 

 characteristics of meteorites. 



The earlier portion of the volume before us details the 

 results of numerous experiments made with the object of 

 explaining different geological phenomena, of which 

 some arc chemical and physical, while others are simply 

 mechanical. 



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