Ventral abdominal sclerotization is generally restricted to the genital plate and anal plate. All other abdominal sclerites are usually dorsal, whether they be marginal, spinal, or entirely covering the aphid's dorsum.
This aphid's dorsum is almost completely sclerotized. Only small gaps exist along the margins and just in front of the siphunculi.
The eighth abdominal segment very frequently has a sclerite, although it is sometimes obscured by the anal plate and cauda in imperfect slide preparations.
The image highlights spinal sclerites on abdominal segments 6, 7, and 8, and four setae located on the eighth abdominal sclerite.
Many alatae have marginal sclerites on abdominal segments 2-4. Sometimes it is dissicult to distinguish between a marginal sclerite on the fifth abdominal segment and an antesiphuncular sclerite.
The arrows highlight the marginal and siphuncular sclerites.
Spinal sclerites are centrally located on the abdominal dorsum, whereas marginal sclerites are located laterally. Many alatae have marginal sclerites on abdominal segments 2-4.
The arrows highlights marginal sclerites on abdominal segments 3 and 4, spinal sclerites on segments 4 and 5, and sclerites in front of and behind the right siphunculus, the antesiphuncular and postsiphuncular sclerites.
Siphunculi may have associated antesiphuncular or postsiphuncular sclerites. Postsiphuncular sclerites are more common and as a general rule an aphid will only have antesiphuncular sclerites if it also has postisphuncular sclerites.
This aphid has strongly pigmented postsiphuncular sclerites, but no antesiphuncular sclerites.
