RHIZOBIIN^]. 81 



reference to this very curious subject of what may be 

 called Paracletism. More correctly, perhaps, its dis- 

 cussion belongs to the historian of Formica than to 

 that of Aphis, since the Ant, with its superior intelli- 

 gence (?), chooses the company of Aphis, and makes 

 it more or less to conform to its own economy. 



But the question arises, and has not been yet satis- 

 factorily answered, what part in the economy of 

 Formica, &c, does Aphis really take ? From the days 

 of Huber the older, and the younger, we have been 

 aware that Ants draw occasional food from these 

 creatures, and this Monograph has already noted that 

 many species of Aphis voluntarily yield honey-dew 

 from their nectaries at the call of the Ants ; but what 

 is to be said of those insects which possess no 

 nectaries, as is the case with the Bhizobiina3 ? 



True, they have certain dorsal pores apart from the 

 stomata ; and in some cases the aerial drops of liquid 

 may be seen to exude from such orifices. 



In these root-feeding Aphides, however, the func- 

 tion of the pores is to exude waxy or silk-like fila- 

 ments, which are employed to cover and protect the 

 insect from the water of the soil and to make a nidus 

 for its eggs. I am far from denying that these pores 

 are capable of giving food to the Ants, but clear obser- 

 vation to substantiate the fact is yet desirable.* 



Perhaps this question may be relevant to the matter : 

 What is the significance of the presence of the blind 

 Claviger, of Julus,of Oniscus, and Scolopendrum, which 

 equally share the shelter of the Ants' nest ? 



It cannot here be argued that they are kept by the 

 Ants for food. The whole question is an interesting 

 one, and is sufficiently puzzling ; for these curious 

 fostering habits obtain also in other Hymenoptera. 

 Thus, the handsome Apathus barbatellus is the petted, 



* Kaltenbach is distinctly of this opinion. He says of Forda, 

 " Dieses Thierchen gibt durch die Afterwarze zuweilen an Tropfchen 

 Fliissigkeit von sich, welche von den Ameisen begierig aufgeleckt 

 wird."— Kalt., « Mon. der Pilau.,' p. 210. 



VOL. IV. 6 



