SYNOPTICAL KEY TO THE APHIDIDAE OF MINNESOTA 127 
stout ; lateral tubercles usually present. Found on trees, or migrating 
to herbs for the summer, or their entire history is passed on herbs. 
Four genera are found in Minnesota, two of which must be indicated 
mas LEW ; 
a. Pleurites on the sides of the body with large glands in place of lateral 
tubercles. The secondary sensoria of the antennae with.wide margins, 
and crowded so as to be transversely oval; cauda short................ 
Genus CEDOAPHIS 41 
b. Pleurites with lateral tubercles in place of glands; secondary sensoria with 
wide margins but not crowded so as to be transversely oval; cauda 
Aphis-like; cornicle narrower at base........... Genus THARGELIA 42 
c. Pleurites with lateral tubercles in place of glands; secondary sensoria 
with narrow border, circular; cornicles short, with spinelike crowded 
reticulations; cauda short and triangular........ Genus ANURAPHIS 43 
d. Pleurites with leteral tubercles, sometimes reduced or wanting; secondary 
sensoria with narrow border and circular; cornicles usually long and 
cylindrical, with open, loose reticuletions; cauda rather long, cone- 
Sushil ere eoyahea harceill Bhs a wale nen BS cleo cioiec cbc ese corte cio Genus APHIS 44 
41. Genus CEDOAPHIS gen. nov. Type: Aphis symphoricarpi 
Thomas, 1878. The pleurites on the sides of the body are provided 
with very large glands in line with the lateral tubercles and cornicles 
when present. These glands are not pulverulent or wax glands, but 
of the same order as the cornicles which are also glandular in function. 
These glands are apparently very primitive structures and are best 
S I ; Y.-J 
seen in the present genus, and again in some of the more generalized 
Callipterini. Their association with the lateral tubercles and cornicles 
opens up a very interesting field in connection with the functions and 
origin of the cornicles so unique and characteristic of the family 
Aphididae. 
(29) CEDOAPHIS SYMPHORICARPI (Thomas) 
Found in distorted leaves of Symphoricarpus. 
42. Genus THARGELIA gen. nov. Type: Aphis albipes Oestlund, 
1887. Pleurites with lateral tubercles in place of glands; cornicles 
narrowed at base and slightly swollen toward the apex; secondary 
sensoria on the antennae with wide margins, but smaller than in the 
preceding genus and not crowded. The secondary sensoria of these 
two genera indicate a distinct form from those found in the rest of 
the family. 
(30) THARGELIA ALBIPES (Oestlund) — 
Found on Symphoricarpus in twisted leaves, sometimes on the 
same bush with the much rarer form Cedoaphis symphoricarpi. 
