large, the rest very small; V with two or three very small ones aa the 
usual large subapical one, “and VI with one large and several small ones 
in a group at base of spur, as usual. T ubercles as*in the females, the 
thoracic directed outwardly, the cauda as in the females. 
Length 1.4 mm., width .7 mm., antenne .9 mm., cornicles .08 mm. 
This species is sufficiently distinguished from Aphis maidis by the 
breadth and large size of the thoracic and abdominal tubercles, which 
are slender and minute in maidis; by the longer beak, which passes the 
middle coxe and usually attains the hind pair, while that of maidis 
seldom reaches the middle cox; by the cornicles, which have a broad 
base, the sides tending to be straight or concave in outline, while in 
maidis the base is narrower, and the outlines more or less convex, these 
varying somewhat, however, so as to mislead in isolated examples ; by 
the cauda, which in the adults is uniformly broadest at base, the sides 
tapering, while in maidis it is somewhat spoon-shaped, broad near 
middle, and narrower between middle and base; by the adults of maidis 
being much more elongate and narrow than adults of this species; and, 
in the winged individuals, by the number and armament of the sensoria 
of the third antennal joint, which are larger than in maidts and rather 
uniform in size, six to eight in number, and arranged in a fairly straight 
row, while there are thirteen to. sixteen visible in maidis, of variable 
size and irregularly distributed along the under side of the joint. 
The oviparous female may be easily recognized by the swollen hind 
tibia, covered with numerous minute sensoria; and the male differs from 
all the wingless individuals in the presence of a few large, and numerous 
minute, sensoria on the antenne. 
ON THE ANTS ATTENDANT UPON THE CORN ROOT APHIS. 
Lasius niger and its variety alienus* are so far the most abundant 
of the seven species of ants w hich we have found in attendance upon the 
corn root aphis that a discussion of the economics of this relation need 
searcely take account of any other species; but as the most promising 
protective measures against this aphis are based on our knowledge of 
the life history and habits of this commonest corn-field ant, an accurate 
account of the latter is to be desired. Our notes on this subject cover | 
the entire period since 1883, and enable me to give a fairly complete 
history of this species throughout the year. 
Life History—The winged sexual forms, male and female, of this 
ant begin to annear each year, as early as the latter part of June (the 
21st eS the 27th), hatching from pupxe which may have formed late in 
May (27 and 28, by our notes). The emergence of males and females 
from the pupa continues throughout the season, certainly into October 
and probably to November, but the males perish before the winter. The 
females, however, having been fertilized and deprived of their wings, 
begin their separate excavations in fall, or continue with the workers in 
nests already established. There they hibernate, sometimes, at least, 
commencing to lay their eggs in fall, and living in spring through April 
and May. 
* [= americanus wherever used in this report.] 
