It is well known that the membranous areas of lepidopterous larvae may lose much of their colour pigment when the larvae are preserved, but it appears to be less widely recognized that the larvae themselves mav also be burned by the preservative. A pale larva, one that is greenish or yellowish when alive and almost cream-coloured when preserved, becomes brownish under these circumstances. The colour change may be so pronounced as to result in mis-identification of the species, and a colour description based on a series of such larvae may be most inaccurate.