•Jan., 1908.] 
Notes on the Aphididae. I. 
243 
NOTES ON THE APHIDIDAE. (I.) 
Observations on a Semi-aquatic Aphid, Aphis aquations n. sp. 
C. F. Jackson. 
This species is a typical representative of the genus Aphis, 
and may be characterized as follows: 
Winged viviparous female. Head broad, sparsely covered 
with hairs, two prominent hairs just above the median ocellus. 
Eves black, prominent, the two lateral ocelli in proximity to 
the two compound eyes; ocular tubercle large. Antennae reach¬ 
ing slightly beyond thorax, joint I and II short, III nearly equal 
to IV and V taken together, slightly imbricated, the posterior 
margin bearing fifteen or more sensories. Joint IV slightly 
longer than V bearing three sensories and imbricated; V closely 
imbricated with two or three sensories near distal end; joint VI 
(including unguis or VII) longer than IV and V taken together; 
the unguis very long and slender, at the base of which is a group 
of six or seven sensories. Total length of antennae 1.6 mm.; 
length of I, 0.08 mm.; II, 0.08 mm.; III, 0.39 mm.; IV, 0.27 mm.; 
V, 0.23 mm.; VI, 0.14 mm.; VII, 0.46 mm. Beak stout, reach¬ 
ing third pair of coxae. Thorax well developed, the pro-thorax 
bearing a distinct lateral tubercle. Each thoracic segment has 
on the ventral side a pair of small wax glands. Wings long and 
narrow, with veins extending nearly to margin, the second branch 
of the cubital not occuring until near the end of that vein. 
Length of fore wing 3.1 mm.; width 1.1 mm.; length of hind 
wing 1.3 mm., width 0.5 mm. Legs long, slender, tibia pro¬ 
vided with four more or less regular rows of long hairs. Femur 
and tibia covered with a fine pulverulence. Abdomen ovate, the 
second and eighth abdominal segments with distinct lateral tu¬ 
bercles above which is found a long bristle like hair. Honey- 
tubes 0.35 mm. long, nearly cylindrical or slightly vase-shaped. 
Cauda conical, provided with two pairs of long recurved hairs; 
outer margin serrated. Length 0.12 mm. Anal plate provided 
with six or eight pairs of long, curved hairs; outer margin of plate 
serrated. Color very variable, abdomen dark green, thorax 
lighter tinged with yellowish. Poorly fed individuals may be 
very light,while old specimens maybe found of an almost uniform 
black color. Total length of body 1.95 mm. Wing expanse, 
7 mm. Immature resembling adult except that the thoracic 
tubercle, wax glands and abdominal tubercles are much more 
prominent, while the cauda does not appear until the third molt. 
Apterous viviparous female Head sparsely covered with 
hairs, eyes black, prominent. Antennae reaching nearly to the 
honey-tubes; joints I and II short, III but slightlv longer than 
