688 RoBert MATHESON 
Further evidence that Fitch has undoubtedly confused Aphis avenae 
Fabr. with Aphis pomi De G. is seen in his third report. Figures 1 and 
5 on Plate I certainly do not represent Aphis avenae Fabr. but are clearly 
illustrations of Aphis pomi De G. His notes also describe the work of 
the latter species. 
It would seem to the writer that Fitch in his first detailed account 
confused the two species, tho undoubtedly Aphis avenae Fabr. was the 
more abundant that season and consequently Fitch’s descriptions are taken 
from specimens of that species. However, one or more of his varieties 
are undoubtedly Aphis pom: De G., but it is difficult to definitely decide 
which. 
If this diagnosis of the facts is correct, Aphis pomi De G. undoubtedly 
occurred in America earlier than 1854. The species doing so much injury 
to the young orchard of Colton (1855) in Vermont were, judging 
from the description of their work, probably Aphis pomi De G. and Aphis 
sorbt Kalt., tho it might be possible that only one species was present. 
Colton reports the work of these lice to have been severe since 1849. 
The work is certainly not that of Aphis avenae Fabr., and it must be 
concluded that either Aphis pomit De G. or Aphis sorbi Kalt. was the 
offender or that both species were present. ‘This would give 1849 as the 
first year in which the species was recorded as doing serious injury to 
young apple trees in the eastern United States. 
Undoubtedly the three species of plant lice, Aphis pomi De G., Aphis 
sorbi Kalt., and Aphis avenae Fabr., which are now common on apple 
thruout the greater part of the United States and Canada, came here 
from Europe in the first half of the nineteenth century. The first records 
of severe injury to apple are from Vermont in 1849, this injury being 
undoubtedly due, in part at least, to the work of Aphis pom: De G. 
Such a record would indicate that this plant louse had been present for 
some considerable time. Unfortunately nearly all the entomologists 
have confused these three species, and it is only by the most painstaking 
effort that it has been possible to offer the tentative synonymical table 
appearing on page 686. The writer feels confident that this species 
has been in America since the middle of the preceding century, tho 
it was not definitely identified until 1897. 
Conclusive evidence that this species was present and widely dis- 
tributed before 1897 is found in the preservation of specimens in Monell’s 
