Jan. 28, 1875] 



NATURE 



H5 



genera derived from the above-named mother famihes. 

 We doubt whether this sweeping and easy way of grouping 

 the American native races will stand the test of rigid 

 ethnologic investigation ; we suspect it will require much 

 wider data than M. JNIarcoy had at his command to 

 settle the question satisfactorily. The facts he gives, 

 however, concerning the various tribes with which he 

 came in contact, appear to us to be of considerable 

 value. His descriptions of the peoples, the manners 

 and customs, ///)'j'/^//i?, traditions, movements, religious 

 beliefs, vocabularies, iS;c., are all contributions to science, 

 which the discriminating ethnologist will no doubt know 

 how to make use of. 



With regard to what must be considered as the proper 

 source of the Amazon, M. Marcoy agrees so far with Mr. 

 Squier, one of the latest writers on the subject, or rather 

 with Dr. Santiago Tavara, of the Peruvian Ilydrographic 

 Commission, that it is not the Maranon. Dr. Tavara 

 decided that as the Ucayali has greater vohmie and length 

 than the Maranon, the former must be regarded as the 

 Rio Madre del Amazonas. M. Marcoy had long before 

 this concluded that as the Apurimac, a principal tribu- 

 tary of the Ucayali, is seventy-five miles longer than the 

 Quillabamba or Urubamba, the upper part of the Ucayali, 

 the former ought to be regarded as the real source of the 

 Amazon. Several attempts have in recent years been 

 made to discover if any of the many upper tributaries 

 on the right bank of the Amazon could be made available 

 for navigation by steamers, but, so far as we have learnt, 

 with disappointing results, so that it is doubtful if any of 

 these immense tributaries can ever be used as pathways 

 for commerce. 



During his slow progress down the Amazon, M, Marcoy 

 frequently halted on its banks, visiting the mission sta- 

 tions, the half-civilised settlements of Brazilians and half- 

 breeds, and the villages of the Indians. He also explored 

 the mouths of some of the rivers flowing into the Amazon, 

 and some of those curious natural canals which unite the 

 main stream with many of its tributaries a considerable 

 distance above the latter's embouchure. It is well known 

 that the waters of some of the Amazonian tributaries, as 

 the Rio Negro, are of a very dark colour, resembling 

 coffee. We do not know that this has yet been satisfac- 

 torily accounted for ; it can hardly, it would seem, be 

 owing to the nature of the ground over which the rivers 

 flow, as this is of very diverse kinds. 1\I. Marcoy declares 

 that when this water is looked at through a transparent 

 vessel, it is perfectly limpid and colourless ; only in cases 

 where the current was slow or imperceptible, it had a 

 brown tint. Animals of all kinds abound in and around 

 these curious waters. 



M. Marcoy made a careful exploration of the delta of 

 the Purus, a large tributary on the right bank of the 

 Amazon, by which he ascertained that the river has 

 only one embouchure, the other openings being really 

 only natural canals. M. Marcoy's knowledge of the 

 hydrography of the south side of the Amazon seems to 

 be clear and accurate, and is certainly extensive, and his 

 frequent dissertations on the subject are worthy the 

 attention of geographers, if they have not already gained 

 it. One of the most valuable features of his work is the 

 set of splendid maps which are prefixed, showing in 

 minute detail the topography of his route, 



We must leave M. Marcoy to find his way to Para and 

 accompany Mr. Keller in his journey up the Madeira. 

 While we certainly think that in regard to the points to 

 which we have referred the value of M. Marcoy's work is 

 capable of being enhanced, still on the whole it must be 

 regarded as deserving to occupy an honourable place 

 among works of travel. It is essentially a popular work, 

 and we hope it may have an extensive sale and many 

 readers, as it contains a vast amount of really valu- 

 able information concerning the geography, topography, 

 natural history, and ethnology of Peru and the Upper 

 Amazon. Messrs. Blackie have done well in publishing 

 an English translation, which has been remarkably well 

 done by Mr. Rich. 



{To be continued.) 



MOCGRIDGE'S " HARVE.STING ANTS AND 

 TRAP-DOOR SPIDERS" 



.Supplement to Harvesting Ants and Trap-door Spidi^rs. 

 By J. Traherne Moggridge, F.L S., F.Z.S. With specific 

 descriptions of the Spiders, by the Rev. O. Pickard- 

 Cambridge. (Reeve and Co., 1S74.) 



MR. MOGGRIDGE'S original work was reviewed in 

 Nature, vol. vii. p. 337, and we have already a 

 mass of additional matter, paged continuously so as to 

 form one volume when bound up with the first part. 

 Only twenty pages are here devoted to the ants, yet we 

 find several observations of great interest to the philo- 

 sophic entomologist. Thus, the actions of lizards and 

 tiger-beetles in attacking the ants were closely observed. 

 The lizards only eat the winged males and females, but 

 show great fear of the workers, always keeping out of 

 their M'ay ; and the workers protect the winged ants by 

 surrounding and swarming over them, so that the lizards 

 can only occasionally dash at an outlying straggler. The 

 Tiger-Beetle {Cicindela) devours the workers, but only 

 attacks them with great precaution, keeping out of the 

 way of the main body and seizing stragglers by a 

 bite just behind the neck. If it fails to seize them 

 in this exact spot it leaves go again, evidently knowing 

 that if the ant's jaws once close on any part of its legs or 

 antenna they will never leave go, even after death. 

 These observations apply to the two species of South 

 European Harvesting Ants, Atta structor and yl. barbara, 

 and they furnish a clue to the use and purport of the 

 large bodies of workers, which act as guards to the males 

 and females. They also explain the use of the spines, 

 hooks, and bristles with which so many of the weaker 

 forms of ants are armed, as well as the occurrence of a 

 proportion of soldiers — large-headed workers whose only 

 function is to attack and drive away certain specially 

 dangerous enemies. Some of these large-headed workers 

 are essentially a huge pair of jaws with just enough body 

 to carry them about, and whose sole object in life is to 

 fasten on some special enemy and sacrifice themselves 

 for the good of the community. The most important 

 problem remaining for solution in connection with these 

 harvesting ants is, how they contrive to keep the seeds 

 in their granaries from germinating. Mr. Moggridge has 

 proved that formic acid or its vapour has no influence, 

 that the presence of the ants is necessary to prevent ger- 

 mination, but that their presence alone does not prevent 



