ANTS AND THEIR GUESTS — WASMANN. 473 



Oecophylla species tliis method of nest construction is general, in 

 the genus Polyrhachis it only pertains to a part of the species, 

 while others construct carton nests. Of the genus Camponotus, 

 finally, it is only known of one species, C. senex of Brazil, and of the 

 genus Technomyrmex we likewise know spun nests with but a single 

 species (T. hicolor textor Forel). 



That ants use their own larvse as weaver's shuttle for spinning, and 

 so utilize the spinning faculty of their larvae in a practical manner for 

 nest construction, is, to be sure, psychologically most remarkable. 

 It is an employment of "tools" which are independent of the body of 

 the animal and do not originate from it, while, for example, the web 

 with which the spider catches its prey is a product of the glands of its 

 own body. Such a well guaranteed and ingenious employment of 

 tools, as the ants demonstrate in the construction of their web nests, 

 we seek in vain elsewhere in free nature, even among the higher ver- 

 tebrates. Yet we must not overestimate this fact psychologically. 

 There are here concerned, as with all other specific modes of nest con- 

 struction in ants, hereditary instincts, over the phylogenetic origin of 

 which, however, the deepest darkness still rests. In any case we 

 must not consider a species of Polyrhachis which constructs webs by 

 means of its larvae as more "intelligent" than another species of the 

 same genus which employs the secretion of its mandibular glands to 

 build a carton nest. In the same wa}" we must not designate 

 Camponotus senex as the "most intelligent " species of its genus because 

 it builds web nests, while other species construct theirs in wood, 

 etc. All the different nest-building instincts are objectively appro- 

 priate in their way, but do not depend upon the intelligent reflec- 

 tion of the individual being, because they prove to be hereditary 

 instincts. Their exercise is, nevertheless, no mere reflex mechan- 

 ism, because it takes place under the influence of the sensory percep- 

 tions and sensory experiences of the individual. Here, too, we must 

 therefore keep ourselves midway between two equally erroneous 

 extremes in the psychological explanation of animal life. Then w^e 

 also shall " learn wisdom " from the ants on considering their ways. 



EXPLANATION OF FIGURES ON PLATES 1-10. 



(The micro-photographs for the most part have been taken with a Zeiss Tessa r 1:6, 3.] 



Plate 1. 



Fig. 1. Formicoxenus nitidulus NyL (sliiniiig guest-aiit), ergatoid male and worker 



(8 : 1). 

 Fig. 2. Formica rufa L. (red liill-ant), queen and .small wurker (3:1). 

 Fig. 3. Formica truncicola Nyl., winged female (4 : 1). 

 Fig. 4. a. 'Worker oi Formica exsecta}iyl. , 



b. Worker of Formica fusca L. (4:1). 

 Fig. 6. Formica sanguifica Lair., worker (3, 5 : 1). 



