Key C. Aphids on larch ( Larix)

Synopsis

C1 (C2) Siphunculi absent. Apterae: antennae with at most 3 segments. Body less than 2.5 mm, often covered with white wax wool or filaments ....................... Adelges Vallot, 1836 p. 24

C2 (C1) Siphunculi present. Antennae with at least 4 segments. Body usually larger than 2.5 mm. Wax, if present, in the form of dusting or well-defined pattern .......................................C3

C3 (C4) Siphunculi present as pores raised on cones ............................... Cinara Curtis, 1835 p. 26

C4 (C3) Siphunculi elongate, tubular ..................................................... Aphis Linnaeus, 1758 p. 27

C1 (C2) Siphunculi absent. Apterae: antennae with at most 3 segments. Body less than 2.5 mm, often covered with white wax wool or filaments ................................. Adelges Vallot, 1836