Dec. ii, 1916 
Macrosiphum granarium 
467 
SUMMER FORMS 
The following description is taken from Pergande (11): 
Apterous female. [PI. B, 2.] Length 2.4 to 2.8 mm.; fusiform, broadest near the 
base of the abdomen. Frontal tubercles large, diverging at the apex, as usual, in this 
genus; antennae bristle-shaped, as long or slightly longer than the abdomen; joint 
six, including the spur, longer than joint three; generally there are one or two small, 
circular and projecting sensoria near the base of the third joint; all of the joints are 
very sparsely beset with short and stiff bristles which are rarely slightly clavate. 
The nectaries are long and reach beyond the tip of the abdomen, though rarely beyond 
the tip of the tail; they are cylindrical, tapering, becoming again slightly stouter 
toward the end. The tail is rather long and stout, curved upward, and about two- 
thirds the length of the nectaries, lanceolate, and more or less distinctly constricted 
about the middle; it is densely covered with acute, minute points and furnished 
each side of its terminal half with three, backward-curved, long bristles. The legs 
are long and provided with short, stiff, and simple hairs. 
The color of the apterous female is yellowish-green, often slightly pruinose; fre¬ 
quently darker toward the end of the body; the head varying from yellow to brownish- 
yellow. The eyes are red to brown, while the tail varies from white to a distinct 
yellow. The antennae, as a rule, are black, though sometimes the first joint may be 
yellow or the first three joints dusky. The terminal half or more of the femora, apex 
of the tibiae, the tarsi, and the nectaries brown to black; the rest of the leg is yellow. 
The body is frequently marked with a brownish puncture or spot each side of the 
prothorax; sometimes there is a narrow dusky or black line, composed of minute spots, 
each side of the mesothorax and a dorso-lateral row of about five linear or rounded, 
blackish or dusky spots each side 6f the abdomen, which sometimes are extremely 
faint or even wanting. Occasionally there are also two additional small black or 
dusky spots between the nectaries. Lateral spots in front of nectaries black. 
Winged migrant. [PI. 33, A.] Expanse of wings 9 to 9.4 mm. ; length of body 
1.4 to 2,6 mm. Antennae long, generally about one-third longer than the body; the 
third joint about one-third shorter than the sixth and provided along its exterior or 
posterior edge with from six to eleven more or less elevated, round sensoria along 
its basal third. The hairs of the various joints are similar to those of the apterous 
female, though sometimes one or the other may be distinctly clavate. The nectaries, 
tail, and legs in general appearance and size are very similar to those of the apterous 
form. The wings are almost twice the length of the body, while the venation cor¬ 
responds very much to that of Aphis. 
Color yellowish green to green; the mesothorax yellow and its lobes brown to black. 
Sometimes a small, oblique, dusky, subdorsal spot and a transverse pale dusky band 
may be observed on the prothorax. Head brown or brownish-yellow; eyes red to 
brown. Antennae black, the first joint sometimes brownish-yellow externally. 
Nectaries black, the tail yellowish or greenish-yellow; sternal plate and lateral spot 
in front of wings black. The abdomen is marked with four or five small, transverse, 
blackish dorso-lateral spots and four black lateral spots in front of nectaries; the colora¬ 
tion of the legs is similar to that of the apterous female. Wings clear, the costa dusky, 
and the subcosta yellow; stigma yellowish, its inner margin dusky; veins yellowish- 
brown, changing to black toward the end. 
It is probably well to state in this connection that the maculation of 
the abdomen is quite a variable character and that the cornicles are 
reticulate at the tip. 
The following measurements (Table II) were made from specimens 
that had been mounted in balsam for over a year. 
