Phthiraptera (parasitic lice).
In 'Identification handbook of the insects and arachnids of Greenland' (J. Böcher, ed.) University of Copenhagen, Copenhagen. N.b. This chapter has been in press for many years. The editors are still waiting for some final chapters before the volume will be published. [2013 UPDATE: This book has been In Press for nearly six years! I'll give it another year, then put the manuscript online or publish elsewhere]