According to Mockford's book(1), in the C. caligonus species group the male has a spur vein off the angle of the pterostigma and has the vertex darkened. The description of the group says the female sometimes has the spur vein and does not say the female never has a darker vertex. The description of C. indicator (= V. indicator) implies that the female of the species does not have these male characters.

Based on color I think the first three photos (two barklice) are male and the other three (two) are female.