41 
vary tosome extent in size, measuring from 1 to1.6™" in length. They 
are of a reddish or purplish-red color, with the prothorax somewhat 
the darkest, the head and rest of the thorax palest, the shoulders 
whitish or yellowish. Eyes brown and the ocellired. Antenne, legs, 
wing-pads, and rostrum pale dusky; the sutures between the antennal 
joints white and the external edge of the wing-pads blackish. All 
are covered with a dense, straight and hair-like, white and glistening 
secretion, which is most dense and brush-like along each side of the 
abdomen; this secretion is apt, however, to be easily detached by the 
movements of the insects within the folds. The antennz are much 
longer than in the preceding stages, and if directed backward would 
reach to or beyond the base of the wing-pads. The third joint is 
much the longest and almost as long as the two last joints combined; 
the fourth and fifth are subequal in length; the sensorial thumb of 
each is minute; the third and fourth are cylindrical and the last one 
slightly tapering, with the usual hairs at the apex. In other respects 
they are similar to those of previous stages. 
Fifth generation; migrant, or fifth stage.—The winged form or 
return migrant is much smaller than those leaving the witch-hazel 
galls, being only about one-half their size. Length of body, 1.6", 
and expanse of wings about 5™". They are dark reddish, the abdo- 
men frequently with a purplish tinge or sometimes greenish-brown. 
Head, antenne, an oblique or triangular depression each side of 
the prothorax, thoracic lobes, sternal plate, and tarsi, black; the 
legs dusky. Wings faintly dusky, the subcosta and stigma dusky, 
the costal cell somewhat paler; veins black. Antenne five-jointed; the 
second joint is almost globular; the third is much the longest; the 
other two subequal in length and together somewhat longer than 
the third; all three are strongly and deeply annulated, the number of 
annulations in each varying more or less; those of the third joint vary 
between 20 and 30; in the fourth between 10 to 13, and in the fifth 
between 14 and 15, though in some specimens there may be but a very 
few and widely separated annulations on the last joint. The legs are 
normal and the digitules of the tarsi, as well as the claws, well devel- 
oped. The head, including the eyes, is about twice as broad as long 
and more or less distinetly conical in front. The tail is knob-like, 
densely covered with minute spines, and bears two long and about six 
smaller bristles. The last abdominal segment is deeply bilobed and 
densely spinous, and bears in addition a number of bristles. 
fifth generation; accessory, apterous female.—In the folds or cor- 
rugations, in company of the winged form, are frequently found 
apterous females, belonging to the fifth generation, which are des- 
tined to produce an additional or intermediate migratory generation. 
The economy of these apterous females and additional migratory 
generations remains rather obscure. 
These accessory females are of a dirty brownish color, and densely 
3504—No. 9—O1——4 
