22 Psyche [April 
magnified), segments as follows: III .0924-.1001 mm., IV (base) 
.0462—.0539 mm., IV (unguis) .0539-.0616 mm., III with a distal 
sensorium and base of IV witha distal group composed of one large 
one and several smaller ones, III as a rule imbricated but not as 
strongly as IV, the whole with a few short spinelike hairs; corni- 
cles short, .0231 mm., broad, cylindrical or very nearly so, and 
rounded at distal end; rostrum reaching to or extending some- 
~what beyond metacoxa (varying in extent. like antenne, with feed- 
ing, as in malifolie@) ; legs armed with spinelike hairs, anterior tibize 
.1463-.1771 mm., intermediate tibiz .1617—.2079, metatibiz .1925— 
.2387 mm.; prothoracic and first and last pairs of abdominal lat- 
eral tubercles comparatively prominent and the last abdominal 
pair usually quite conspicuous—(all lose in conspicuousness as the 
insect body enlarges, but under higher magnification the last ab- 
dominal pair is quite easily made out in live specimens which have 
not fed too far, and is a very good distinguishing character) ; length 
of body .5236—-.8162 mm., width af widest part .2772—.4004 mm. 
3. A. prunifoliz Fitch (Apple-Grain Aphis). 
Dull light green or dull dark green, anterior and dorsal aspects of 
head dusky to blackish and very often with a pale or uncolored 
median longitudinal line; antenne, base of rostrum, caudal end of 
abdomen ventrally, and legs dusky—distal portions of femora, 
tibiae, and of tarsi may be still darker; cornicles and about 4 distal 
portion of rostrum black or blackish; eyes black 
(in mounted specimens deep red). Newly- 
hatched specimens are light green, with head 
and thorax (at least first two segments) still 
lighter or pale yellow-green; appendages with 
a cast of the color of the body, although practi- 
cally colorless in part sometimes; femora us- 
ually yellow-green. 
Antenne stoutish, reaching to about end of 
thorax and “shortening up” somewhat with 
feeding, flagellum or unguis about twice as long 
as base, segments as follows: III .0924-.1001 
Fig. 3—Antenna mm., IV (base) .0385—.0462 mm., IV (unguis) 
andcornicleof Aphis 9847-1001 mm., III with a distal sensorium 
runifoie Fitch, Str te : 
id 150. and base of IV with a distal group composed 
