738 RosBert MATHESON 
a reddish yellow; the head, the distal half of the antennae, the cornicles, 
and the distal ends of tibiae and tarsi, are black; the femora and the 
proximal parts of the tibiae are yellow. The entire body is covered with 
a rather dense white pulverulence. The lateral and caudal tubercles are 
present and appear as small dark spots. 
Fifth instar, mature winged female (spring migrant) (Plate XXIV).— 
Length 1.44-2 mm.; width (wing expanse) 5-6 mm.; cornicles 0.32- 
0.38 mm. long. 
The head is black above, with the median ocellus protruding and appear- 
ing as a tubercle. The antennae, the dorsal part of the thorax, a large 
quadrate area on the dorsum of the abdomen, the cornicles, the distal 
half of the femora, the distal ends of the tibiae, and the tarsi, are black; 
the proximal ends of the femora, and the tibiae except the tips, are yellow- 
ish brown; on each lateral margin of the abdomen in front of the cor- 
nicles are three rounded black areas; in front of the large quadrate black 
spot on the dbdomen there are narrow transverse black lines in some 
specimens, but these are frequently lacking; around the base of the cor- 
nicles the color is black, and this is often fused with the black quadrate 
areas; the remainder of the body is of a yellowish brown color. The 
wings are hyaline, with the veins thin and the stigma dusky. The eyes 
are tuberculate and black; on the vertex between them is a pair of small 
tubercles. The prothorax has a prominent tubercle on each side. The 
abdomen has small but distinct lateral tubercles and prominent 
dorsal tubercles on the last two segments. The cauda is conical, short, 
setose, and provided with two or three pairs of long curving hairs. The 
cornicles are cylindrical, faintly imbricated, curved, and distinctly flanged 
on the distal end (fig. 115, c, page 706). 
The antennae (fig. 114, c, page 705) are 6-jointed. Segments I and II ar 
imbricated on their inner margins and armed with a few short, sharp 
spines; Segment III has numerous sensoria, varying from 50 to 60, th 
imbrications showing faintly; Segment IV is similar to Segment III, bu 
bears only about half the number of sensoria, varying from 20 to 30 
Segment V has only from 4 to 10 sensoria, and the imbrications ar 
more distinct; Segment VI is strongly imbricated, and the unguis is shor 
and bears the usual group of sensoria at its distal end. The lengt 
of the segments is as follows: Segment III, 0.6-0.7 mm.; Segmen 
IV, 0.44 mm.; Segment V, 0.28 mm.; Segment VI, 0.12 + 0.56 mm. 
