BIOLOGICAL STUDIES ON THREE APHIDIDiE. 135 



antenna (alcoholic specimen), I, 0.040 mm.; II, 0.040 mm.; Ill, 

 0.101 mm. ; IV, 0.050 mm. ; V, basal, 0.061 mm. ; filament, 0.098 mm. ; 

 total, 0.390 mm. 



After third molt. — General color light chrominm-green. Head 

 with pale brownish tint. Ultimate and part of the penultimate seg- 

 ments of the antennae darkened. Antenna with only .5 distinct seg- 

 ments; a slight constriction in the third shows the commencing of 

 the formation of another segment. Eyes reddish brown. Legs dark, 

 the tarsus and distal ends of the femur and tibia being almost black. 

 Tip of abdomen dark, as are also the cornicles, which are darkest at 

 the apex. Cornicles noticeably longer than in preceding stages; 

 basal half more or less swollen and the tip slightly dilated. Measure- 

 ments: Length of body, 2.063 mm.; width, 0.981 mm.; cornicles, 

 0.127 mm.; antenna (alcoholic specimens), I, 0.064 mm.; II, 

 0.064 mm.; Ill, 0.183 mm.; IV, 0.067 mm.; V, basal, 0.071 mm.; fila- 

 ment, 0.112 mm.; total, 0.561 mm. 



Adult wingless virljjarous female. — Head black. Thoracic and 

 first abdominal segments with median transverse black markings, 

 the prothorax being almost entirely black. On each side of the ab- 

 domen are 2 parallel rows of minute black markings — one on each 

 side of the cornicle. These rows are not constant, the upper one some- 

 times being indistinct or wanting. Posterior 3 segments of abdomen 

 with black transverse median markings. Eyes reddish brown. All of 

 antenna dusky except the third segment. Cornicles and tips of style 

 black. Coxae, most of the femora, apex of tibiae, and the tarsi black. 

 Measurements : Length of body, 2.09 mm. ; wddth, 1.036 mm. ; antenna, 



1, 0.036 mm.; II, 0.054 mm.; Ill, 0.181 mm.; IV, 0.091 mm.; V, 

 0.091 mm. ; VI, basal, 0.109 mm. ; filament, 0.118 mm. ; total, 0.680 mm. 



Winged viviparous female. — Head black, thorax blackish, abdo- 

 men pale green, with a black marking on each side of the second, 

 third, and fourth segments; transverse black markings on the last 



2, and sometimes last 3, segments; a black ring around each cor- 

 nicle, and a few small black markings irregularly scattered over 

 abdomen. Antennae dark; usually 7 or 8 sensoria on the third seg- 

 ment, sometimes only 6 ; 1 sensorium near the apex of each of the 

 fourth and fifth segments; several more or less distinct sensoria at 

 the apex of the basal portion of the sixth. Eyes dark reddish-brown. 

 Cornicles and style as in wingless pseudogynes. Measurements (alco- 

 holic specimens): Length of body, 1.468 mm.; width, 0.605 mm. 

 length of wing, 2.33 mm.; antenna, I, 0.036 mm.; II, 0.055 mm. 

 Ill, 0.187 mm. ; IV, 0.095 mm. ; V, 0.106 mm. ; VI, basal, 0.099 mm. 

 filament, 0.194 mm.; total, 0.772 mm. 



