Expression of Dll and En in two saturniid species in the late larval wings, two to three days after the start of cocoon spinning. (A) Left and right forewings of Saturnia pavonia, showing Dll expressed in the margin (red) and also in future discal-eyespot centers (arrows and insets), together with En (green insets), two days after the beginning of cocoon spinning. The black marking next to the Dll- and En-expressing cells of the left wing appears to be a piece of debris, whereas the darker spots overlying these same cells on the right wing appear to be small pieces of trachea. (B) Hindwing of Saturnia pavonia showing an enlarged focus expressing Dll and En at the future discal-eyespot center. Note the absence of a cross vein at this stage. The area showing double staining in the bottom right sector of the wing represents a fold of the wing margin over part of the wing. (C) Hindwing of Antheraea polyphemus three days after beginning of cocoon spinning showing En present in a line marking the elongated central axis of the future discal-cell eyespot. In the pupal stages of both saturniids a cross vein will appear between M2 and M3, presumably at the position where En and Dll are expressed (see  for venation notation). All panels at 50× and insets at 100×.