IG THE CANADIAN ENTOMOLOGIST. 



the bases of young peach trees from the surface of the ground to the 

 crown, and when the soil is somewhat heavy and packed closely about 

 the base of the tree, these burrows are excavated close to the bark, which 

 is here very soft and tender, and in some cases even the bark itself has 

 been gnawed away, thereby giving the surface an irregularly grooved 

 appearance, but clearly marking the directions of the burrows. This 

 disposes of the question of the ability of this ant to excavate in the 

 tender bark of the roots and about the crown of young peach trees. 



Below ground I always find this aphis clustered on the most tender 

 roots or rootlets, as stated by Dr. Smith, and with ants in constant 

 attendance, promptly removing their wards whenever these are brought 

 to light by my digging. But in cases where there was a lack of rootlets, 

 a condition of affairs was encountered that was alike perplexing and 

 interesting. The bases of some of the roots, and also the crown, had 

 patches of bark removed and the wounds had every appearance of having 

 been caused by the gnawing away of the bark, the detached bits inter- 

 mixed with the escaping sap being present, and the most persistent search 

 failed to reveal any organism capable of doing this, except the ants, of 

 whose ability to gnaw the tender bark of the lower portion of the tree 

 there was ample evidence between the crown and the surface of the 

 ground. The object of these wounds, however, did not appear clear to 

 me until on further examination it was found that where these wounds 

 had begun to heal over, the lips thereof were closely packed with root 

 lice, attended by this ant. It appears that this aphis can subsist from this 

 tender growth of over-healing bark, as well as if they were colonized on 

 the tender rootlets, and in the former case they maybe observed collected 

 along the edges of the wound precisely as does Schizoneiira laiiigera, 

 about the overgrowing bark on the apple, in cases of wounds caused by a 

 pruning off of a large limb. Where the wounds on the peach roots were 

 infested by the aphis all bits of gum and detached bark had, seemingly, 

 been removed, thus leaving a clear area for the work of the aphis, and 

 here as elsewhere the ants were carefully looking after them. 



When we come to recall the influence of other species of ants, and 

 especially other members of this genus Lasius, on other species of 

 aphides, it is impossible for me to escape the conclusion that we here 

 have ample grounds for accusing Lasius ainericanus with intentionally 

 gnawing the bark on the roots in order to furnish a supply of food for 

 Aphis pricnicola, Kalt., where there is a lack of rootlets for the required 

 pasturage, f 



tRead before the Ohio vState Academy of Science, December 29, 1898. 



