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likely the aphides are also carried to parts above ground, which 

 these ants also frequent. That they actually bring the aphides out 

 of the earth has not been established by observation, but there- can 

 be no reasonable doubt. It is probable that many, at least, of the 

 colonies which appear on the parts above ground in the early Spring 

 have not come from Winter eggs, but from the root-infesting pseu- 

 dogynae. I believe this to be true for the following reasons: i, The 

 wingless viviparae are to be found on the roots at this season in com- 

 pany with an ant which takes a very special interest in them; 2, The 

 same form generally appears above ground first upon short spurs 

 which have recently grown from the trunk and lower, branches near 

 the earth, and migrates to remoter parts of the tree only after several 

 days or weeks; 3, In the Spring of 1890, in an old, root-infested 

 orchard, they appeared upon the chance seedlings which were com- 

 ing up all over the orchard, just as soon as they did upon the older 

 trees. This orchard was plowed a few weeks previous, after which 

 the stones germinated and the seedlings pushed through the fur- 

 rows. They attacked the young plants as soon as they reached the 

 surface of the earth, and probably before. I examined a great many 

 of these tiny seedlings and found every one infested. At this time, 

 in this orchard, colonies were just beginning to appear upon short 

 succulent growths on the trunk and lower limbs, but none could be 

 found upon the upper and outer limbs until considerably later. 

 There is no reason to suppose that the colonies which I found on 

 the seedlings at the surface of the earth and under it, crawled from 

 the distant tops of the older trees, or were carried from them. It 

 is much easier to think of them as coming from the infested net- 

 work of roots only a few inches away. In both cases I think the 

 aphides crawled out of the earth, or were brought out by the yellow 

 ant. 



I first collected the winged viviparous form at Still Pond, Md., 

 in April, 1889. Soon afterwards I took it at Dover, Del, and con- 

 tinued to find it till June. In 1890, it was sent to me from Calvert 

 County, Md., as early as April 14th. At Dover I could find none 

 until April 23d, and even then those which I obtained were from a 

 limb plucked three days previous and kept in the house, where it 

 dried up gradually. The disappearance of the food supply probably 

 hastened the metamorphosis, for there were none on the branch 

 when it was brought in, and none to be found in the orchards until 

 some days later. At Still Pond I found it abundant from May 5th 

 to 19th. It was also plentiful at this time in orchards around Dover. 

 A few days later I saw it in Caroline County, Md., but both forms 

 . were then becoming scarce. 



