Cocoons of woolly doom

Back in the day, wardrobes and blanket-boxes smelled of mothballs (largely naphthalene though it was flammable, and camphor is a less toxic alternative) placed to keep fabric-eating moths of the family Tineidae away. Now, they are less common as the moth larvae do not eat synthetic materials, and on the whole houses are cleaner and more hygeinic. However, in forgotten cupboards, they still nibble their way through wool and other animal materials such as furs. The adults tend to be rather drab, but as I found out while clearing a cupboard of woollen items in the attic, the larvae of one species, Tinea pellionella, the case-bearing clothes moth can produce something rather colourful (if also annoying) - their cases or cocoons.

A larval case of Tinea pellionella

The larval case above is clearly made of fibres spun from differently coloured wools (the ones with the holes in...) and in its own way is quite a beautiful thing. It is dorso-ventrally flattened, and the ends are open; thus the larva's front end can protrude to allow feeding and faeces can be ejected (the rear is bottom-right and shows small dark faecal pellets). The moth pupates in the case which is fixed some distance from where it feeds and then emerges, leaving the empty skin protruding. The group as a whole can be difficult to identify, often requiring dissection of adults.

A case of T. pellionella with protruding skin after emergence

Having found (and squashed, sorry) quite a number of these, I hope that I won't need to sew up any more holes - fortunately I'd noticed a few adults flying around and realised that the larvae needed to be found; so, with  a bit of luck the infestation will remain minor, and I'll be off to buy some cedarwood repellent, though the number of dried husks also indicated that our house-spiders were doing a useful job!

A smaller, brighter case of T. pellionella.

Further reading

Heath, J. & Emmet, A.M. (1985). The Moths and Butterflies of Great Britain and Ireland. Volume 2: Cossidae - Heliodinidae. Harley, Colchester. [Part of the impressive (but sometimes expensive) MBGBI series covering all Lepidoptera of the British Isles in considerable detail, including dissection of genitalia]
Palmer, R.M., Porter, J. & Collins, G.A. (2012). Smaller Moths of Surrey. Surrey Wildlife Trust, Woking. [Distribution maps for the county of Surrey, but much information which is more widely applicable]
Stirling, P., Parsons, M. & Lewington, R. (2012). Field Guide to the Micromoths of Great Britain and Ireland. BWP, Gillingham. [excellent affordable guide]