The present study describes the relationship between the morphology of the forewing axillary sclerites and the way the wings fold among 24 aphid genera as compared to a representative of coccids. Architecture of the forewing base was imaged with scanning electron and optical (fluorescence) microscopy. Significant differences in morphology of axillary sclerites between aphid species were observed, despite their belonging to one infraorder. Detailed description of 41 features of axillary sclerites was made. There was no difference between axillaries of viviparous (Aphididae) and oviparous (Adelges sp., Phylloxera sp.) species. No clear relationship between morphology of the axillary sclerites and the wing folding could be confirmed. Instead, the thorax structure determines the way the wing folds in aphids. Phylogenetic analysis based on our results cannot be conducted at this stage of study. To show how three-dimensional the structures are and how difficult to describe, a short animation of Aphis fabae (Aphididae) wing base was added. This is a preliminary study about morphology of axillary sclerites among aphids.
Keywords: Aphids; Axillary sclerites; Wing base; Wings folding.