12 I.Tiine, 



The Hocks of cuttle of these ants were thus not only increased in 

 numbers but also in species. Another thing which somewhat surprised 

 me, was that the ants, in order to be easily within reach to assist and 

 defend their cattle, had excavated in several parts of the stalk and of 

 the larger ribs of the leaf true guard-houses of an ingenious structure. 

 Each had an opening sufficiently wide to admit the passage of the 

 largest Tpttujomcira. This opening led to a gallery excavated in the 

 pith of the stalk to the depth of four inches or more. Besides this 

 main opening, there were hollowed out two or three very small holes, 

 with what object I cannot say, but 2>i'obably with the view of ven- 

 tilating the domicile, a current of air passing from the larger opening 

 to the smaller ones. The greater part of the Tettigometrce remained 

 outside these shelters, but some had penetx'ated within and had also 

 deposited eggs there. 



The cardoon plaiits, strange as it may seem, which had been con- 

 tinuouslv punctured for months by the larvie of Tciliciomctra and 

 Issus, and which were also pricked and sucked by the ants, as 1 had 

 several times observed, and which had long galleries excavated in the 

 pith, were notwithstanding in a most vigorous state of vegetation and 

 fruiting most copiously, thus showing that they suffered little or 

 nothing from the presence of so many visitors. 



The affection of the individuals of Formica puheHcens for these 

 colonics of Tcttigomctra and Issns is truly great. It was evidently 

 with the intention of watching better over them that these habitations 

 had been excavated. The lives of these cattle of theirs are exposed to 

 the attacks of many enemies. I observed spiders, Coccinellce, and 

 ichneumons. I found one ichneumon of proportionate size, dead, with 

 its abdomen torn, which had probably been the work of these guardians. 



On the whole it would appear from these phenomena that in 

 Cynara carduncidus and C. sco/i/mus, which is probably only a variety 

 induced by cultivation, we have a true species of European Eormi- 

 carium, comparable to a certain point and analogous to the Myrmecodium 

 and Hydnophythum of Asia, and to the Tococa and Mojeta of America. 

 One thing seems certain, that on a plant on which the ants have fixed 

 their abode, caterpillars and other foes to vegetables cannot also occur. 

 Hence we have here an example, unique as far as we know, of a 

 "quadruple alliance" between four different beings, that is between 

 Cynara cardunculus, Trftiyomctra, Iiisus and Formica. 



May I2lh, 1874. 



