(pl siphunculi). A pair of rod-like appendages on the abdomen, an exclusive character of the family Aphididae, aphids. The exude a viscous liquid containing mainly excess sugars – to obtain the necessary amount of amino acids, aphids need to digest much liquid, and ingest much more sugars than needed. Shape, sculpture and even colour of the siphunculi are diagnostic. In some instances they are reduced to no more than flat pores.

Pterocomma salicis: aptera on Salix alba

The siphunculi of Pterocomma salicis are the most conspicuous