54 GENERAL BIOLOGY 



Study y. Observations on ants a^td aphids. 



It is not possible to give a hard and fast outline for the 

 study of these phenomena : for, thoughwidespread, they are 

 not equally available at all times and everywhere. It 

 should be possible to find anywhere in summer a number of 

 colonies of aphids with ants in attendance, on such plants as 

 curled dock, milkweed, thistle, dogwood, etc. Ants are 

 easily seen when running about over green vegetation, and 

 almost always there will be found flocks of aphids (or of other 

 honey dew secreting hemiptera with which the ants have 

 similar relations) as the occasion for their assembling. 



Such an association being found, the apparatus needed 

 will be a low power magnifier (such as a reading glass is ex- 

 cellent) and a note book, and the things to be observed are: 



i) The ordinary behavior of the ants toward the flock. 



2) The gentleness of the ants toward individual aphids: 

 the stroking and patting of them first with the antennae and 

 coming closer, with the palpi. 



3) The lapping up of the honey dew when an aphid 

 responds by ejecting it. 



4) The ferocity of the ants toward intruders : this may be 

 tested with one's own finger. 



5) The stupid indifference of the ants toward the eggs 

 and larvae of the parasites. 



6) The general inactivity and helplessness of the aphids. 



7) The prevalence of (parchment skinned) parasitized 

 individuals. 



If aphid sheds can be found, their materials and con- 

 vStruction should be noted, their doors, their braces, and 

 their shape as adapted for giving a maximum amount of 

 foraging surface with a minimum of construction. Some 

 advantages to both ants and aphids can readily be seen to 

 accrue from them. 



