66 SEVENTEENTH Report STATE ENTOMOLOGIST OF MINNESOTA—1918 
greatly differentiated that the number of genera is proportionally great. 
The positive characters of the Aphidinae, the development of the 
antennae, frontal tubercles, spur, venation, cornicles and cauda, all 
appear as negative in the Pemphiginae. Positive characters of the 
Pemphiginae are seen in the great development of the dermal glands 
arranged into areas, often very conspicuous on account of the secre- 
tion of waxy substance under which many of them find protection; gall 
structure is also a very positive character of the group. While the 
Aphidinae live more or less exposed, depending more on their extra- 
ordinary power of reproduction in order to hold their own, the Pem- 
phiginae, on the other hand, seek protection by concealing themselves, 
under wax, in crevices of bark, in folds of leaves, in true galls, or 
underground on roots of plants. This instinct may be considered as the 
distinguishing character of the subfamily, which has expressed itself 
in all their structures. 
KEY TO THE GROUPS OF THE PEMPHIGINAE 
1. Fundatrix with six segments to the antennae; sexes with rostrum; found on 
bark of woody plants. .. . VI- Group PHYLLAPHIDINA 
—-Fundatrix with fewer than six segments to the antennae; sexes usually without 
rostrum; usually found on leaves of trees and woody plants. . . . 2. 
2. Radial sector arising from the radius back of the stigma, or from the prox- 
imal end of the stigma; found on conifers. . . VII. Group MINDARINA 
—Radial sector arising from the middle of the stigma; usually some of the gen- 
erations are found in twisted or folded leaves or producing true galls on trees or 
woody plants. . . 3. 
3. TIundatrix with five segments to the antennae; often found in pseudogalls, i.e., 
twisted or folded leaves of trees. . . VIII. Group SCHIZONEURINA 
—Fundatrix with four segments to the antennae; usually found in true galls 
produced on tender twigs, buds, or leaves of trees. . . . IX. Group PEMPHIGINA 
Vike Group PidyY LEAP EIDINA: 
Koch, 1854, Die Pflanzenl. Heft 1. Sub Phyllaphiden (tribe). 
Passerini, 1868, Aphid. Ital. Sub Lachninae (subfamily). 
Mordwilko, 1908, Acad. Imped. Vol. 18. Sub Callipterini (tribe). 
Koch (1854) first recognized the present group under the tribal 
name Phyllaphiden which is a nomen nudum.  Passerini (1863) placed 
Koch’s Phyllaphis in the subfamily Lachninae. Mordwilko (1908) 
considers it under the tribe Callipterini. Authors up to the present 
have considered Phyllaphis under the Aphidinae on account of the 
two-branched media, while in other respects it shows the characters of 
the true Pemphiginae and should be considered as such. 
Morphological characters. Front convex. Antennae short, have 
six segments and a very short spur; articulated to the head in shallow 
depressions or pockets; sensilla short and few (Phyllaphis), or long 
