426 INTRODUCTION TO ZOOLOGY chap. 



to bring in fresh leaves on which to grow fresh fungus 

 threads. From this time onward the larvae are only fed on 

 the fungus, and the queen leaves off her horticultural efforts 

 and gives herself up entirely to increasing her family. 



Some of these leaf-cutting ants, such as Atta texana of 

 Texas, do an enormous amount of harm to the plants around 

 the nest. This species has three kinds of worker ants — the 

 smallest appear to spend their time tending the fungus beds, 

 keeping them carefully weeded of any other growths ; the 

 medium-sized forms go out and cut the leaves and prepare 

 new beds of them ; whilst the larger ants guard the nest. 



The accounts of these fungus-growing ants given by 

 different investigators read like fairy tales, and yet they have 

 been vouched for again and again by competent observers, so 

 that we can but accept them, and wonder over them, at the 

 same time bearing in mind the words of the old Dutch writer 

 Swammerdam, who, writing over two hundred years ago, 

 said : "I can only recommend it to every one who shall be 

 desirous of knowing the truth, to consult the insects them- 

 selves, for nature far surpasses all the writings and treatises 

 that may be compiled." 



Classification of the Ants mentioned in Chapter XXVI. 



Sub-order. Hymbnoptera aculbata (the Stinging Hymenoptera). 

 Division 4. Heterogyna ( = Family 6. Formicidae). Social 

 forms, always with differentiation into three 

 castes of individuals, 5 $ and S . 



The first, or first two, abdominal segments — 

 not reckoning that segment which is fused 

 with the thorax — form " nodes," small knot- 

 like segments, with very mobile articulation. 

 Sub-family 1. Gwmponotides. One node only is present, bear- 

 ing a flat elevated scale. There is no sting, 

 though poison can be ejected from the 

 modified sting structure. 



Pupae usually enclosed in cocoons. 

 'F. sanguinea (the Blood - red Slave- 

 making Ant). 

 Genera. Formica. iF. rufa (the Wood Ant or Red Horse 

 Ant). 

 .F.fusca (the Dusky Slave Ant). 



