SYNOPTICAL KEY TO THE APHIDIDAE OF MINNESOTA 121 
18. Tribe TRAMINI. Distinguished by the very long tarsal joint 
of the hind legs. [Found on roots of plants and in nests of ants. No 
representative of this tribe has been recorded from Minnesota, but 
probably occurs. They must be looked for on roots of plants (trees 
‘and Compositae) and also in nests of ants. 
19. Series LACHNEA-APHIDEA. Antennae 6-jointed, rarely 
only 5-jointed; spur of terminal segment as long as or longer than 
the basal part; sensilla of the antennae hair-like or spinelike ; cornicles 
short and truncate, or long and cylindrical; cauda usually obvious 
and projecting beyond the rounded anal plate. The series includes 
two supertribes : 
a. Antennae usually shorter than the body, with numerous long, curved 
hairs like those in Lachnus; spur usually much longer than the basal 
part; cornicles short and of the truncated type, not longer than broad, 
Omuimlonger then swollens.a.). .ct.ccs + te Supertribe CHAITOPHOREA 20 
b. Antennae usually as long 2s or longer than the body; sensilla on the 
antennae usually short and spinelike with a pointed apex; cornicles cylin- 
dricel and much longer than broad, sometimes very short and small or 
SATO ee tegen ery AU an cfm rayne tree ere Nee natin clererteae 7c a Supertribe APHIDEA 29 
20. Supertribe CHAITOPHOREA. The long, spreading, curved 
hairs of the body and appendages are characteristic of the Chaito- 
phorea. While some are still found on the bark and woody parts of 
trees, most of them have become adapted to live on the leaves and 
succulent growth of their host plant. There is an obvious and easy 
transition fom the Lachnea to the Chaitophorea. Two tribes are 
represented in Minnesota: 
a. Usually large forms found on woody parts of treés; cornicles longer 
then broad and swollen, rarely cylindrical, and usually pale, yellow or 
red, contrasting with the darker colors of the body................... 
Tribe PTEROCOMMINI a1 
b. In size medium to very smell and depressed forms found on leaves and 
succulent growths of trees, rarely on the woody parts; cornicles short 
and truncate, rarely absent; cauda triangular, extending beyond the 
Anlaleen Ate ser OsStnuil esos miss eter Tribe CHAITOPHORINI 25 
/ 
21. Tribe PTEROCOMMINI. The Pterocommini represent the 
generalized Chaitophorea which stand nearest to the Lachnea as seen 
in their large size, shorter antennae, and moderately long spur in 
comparison with the more highly specialized Chaitophorini; they are 
all bark feeders on woody plants. Characters in advance over the 
Lachnea are their shorter legs, enlarged cornicles. The lateral 
tubercles of the body are also better preserved than in the Lachnea. 
Representatives of three genera are known from Minnesota: 
