116 NINETEENTH REPORT STATE ENTOMOLOGIST OF MINNESOTA—IQ22 
discarding the term Chermes that has been current in literature for 
a century or more. An obvious distinguishing character is the ab- 
sence of the stigmal vein (radical sector) in the Chemesidae, and the 
simple media which appears as a stigmal vein. In the Aphididae the 
radial sector appears as a distinct vein and only very exceptionally 
is it reduced or wanting ; the media is usually once or twice branched. 
In the following key only the family Aphididae is treated. . . . . 2. 
2. Family APHIDIDAE. Tarsi 2-jointed; antennae usually 
6-jointed, the terminal segment with a slender prolongation or spur ; 
wings transparent and with characteristic aphidian venation. Ab- 
domen with a pair of dorsal tubes, or cornicles, on the posterior end, 
sometimes very short or wanting; the last segment of the abdomen 
with a more or less obvious dorsal projection, the cauda, and usually 
with a less obvious ventral projection, the anal plate. Passerini 
divides the family into several subfamilies, but the best writers of the 
present admit only two: 
a. Living exposed on plants. Typical Aphididze in which the antennae, cor- 
nicles, and cauda show a tendency to increase in size and complexity ; 
sensoria, on ‘the antennae usually circulars. i...) se 5! WEISMAN a 
b. Living concealed under woody secretions, in folded leaves, in galls, or 
underground on roots; antennae, cornicles, and cauda show a tendency 
to become reduced or lost; sensoria on antennae usually transverse or 
ATTA ARE, “Aye Aho ee aniegs exe ee RES a a Ee oe PEMPHIGINAE 106 
3. Subfamily APHIDINAE. Antennae always longer than the 
head and thorax, usually half as long, equal to, or longer than the 
body; spur of the terminal antennal segment much longer than the 
basal part, sometimes equal to it or shorter in the more generalized 
forms. Cornicles obvious as cylindrical tubes; cauda usually well 
developed. The fifteen or more tribes of the subfamily may be 
grouped in three series of tribes: 
a. Spur short; body end appendages thickly covered with long spreading 
hairs; found on trunk and limbs of woody plants..................... 
Bi creative me owe Series LACHNEA PROPER 4 
b. Spur long; hairs on the antennae usually short and spinelike; found on 
leaves of trees, on tender growing twigs, or om herbs...............7-5 
ies aoe Series LACHNEA-APHIDEA 19 
ce. Spur long; hairs on the antennee and usually on the body with enlarged 
apices or globate (capitate) ; feeding on leaves of trees or on herba- 
CEOUSMP ANUS imine etc oe. eee Series LACHNEA-MACROSIPHEA 62 
4. Series LACHNEA PROPER. Antennae about half, the length 
of the body; terminal segment with a very short spur (unguis) ; body 
and appendages thickly covered with long, slender hairs and sensilla; 
