Still, there are occasional facts on record, which would tend to prove that even these are not altogether exempt from the deranging force of certain contingencies from without: the number of the antennal joints, for instance, in the tribes where those organs are multiarticulate, is said to vary; but how far this may be dependent on physical influences, I am not in a position to decide.
"On the Variation of Species, with Especial Reference to the Insecta ; Followed by an Inquiry into the Nature of Genera"
Thomas Vernon Wollaston
The Common Skippers are smaller, and have very large heads with the antennal clubs drawn out and recurved.
"Butterflies Worth Knowing"
Clarence M. Weed