Jan., 1908.] 
Notes on the Aphididae. I. 
249 
believe that their production is dependent on either climatic 
conditions or changes in the food plant. At present further 
experiments are being conducted along this line. So far as I am 
informed this species has never been described or the peculiar 
adaptations of its structure to its semi-aquatic life noted. 
Ohio State University, Columbus, Ohio. 
Note. —Since this paper was written specimens have been 
received from Professor R. A. Harper, of Wisconsin .State Uni¬ 
versity which prove to be identical with this species. Professor 
Harper reports them very troublesome on a number of water 
plants in the University green house. 
EXPLANATION OF PLATES. 
A. —Nymph of apterous viviparous female before first molt. 
Fig. 1 . Dorsal outline of head and thorax, showing antennae. 
compound eye, thoracic tubercle, and the three thor¬ 
acic wax glands. B. & L. 1 in.—-j in. 
Fig. 2 . Dorsal outline of the posterior region of abdomen showing 
honey-tube within which are small characteristic 
bodies and a fine tube which resmbles a trachea. Also 
the two abdominal tubercles, their accompanying 
hairs and the anal plate. B. & L. 1 in.—-§ in. 
Fig. 3 . Sensory pits at base of unguis. B & L. 1 in.—$ in 
Fig. 4 . Distal portion of tibia and tarsus, the former showing 
the regular arrangement of the long hairs, and also 
the pulverulent character of its surface. B. & L. 
2 in.—£ in. 
Fig 5 Dorsal view of insect. B. & B. 2 in.—§ in. with lower 
lens removed. 
B. —Drawings of the adult apterous viviparous female. 
Fig. (i. Outline of head showing adult form of Fig. 1 . B. & L. 
1 in.—§ in. 
Fig. 7 . Outline of abdomen showing adult form of Fig. 2 with 
cauda developed. B. & L. 1 in.—§ in. 
Fig. 8 . Adult apterous viviparous female. B. & L. 2 in.—3 in. 
with lower lense removed. 
C. —Drawing of adult winged viviparous female. 
Fig. 9 . Outline of head showing ocelli and antennal sensories. 
B. & L. 1 in.—§ in. 
Fig. 10 . Abdomen of above. B . & L. 1 in.—J in 
Fig. 11 . Adult winged viviparous female. B. & L. 2 in—§ in. 
with lower lense removed. 
Note. —The above drawings were made with the use of the camera 
lucida at table distance. A Bausch and Lomb microscope was used 
with the combinations indicated. 
