http://www.collembola.org/slides/setaea05.htm - Last updated on 2001.09.05 by Frans Janssens
Checklist of the Collembola: Morphology of the setae: slide 5 of 14


Fig.5. Setae with a positive shaft diameter gradient. Janssens, F. © 1999.
Positive proximodistal shaft diameter gradient
The positive proximodistal gradient of the diameter of the shaft results in an upside-down conic biconvex shaft profile of the clublike setae, such as the macrochaetae recorded from Cyphoderus. This gradient is implicitly non-linear and illustrates a differentiation in the setal shaft: while the main body of the shaft has a positive proximodistal diameter gradient, the apex of the shaft has a negative diameter gradient.