WordNet (r) 3.0 (2006):

tsetse fly
    n 1: bloodsucking African fly; transmits sleeping sickness etc.
         [syn: tsetse fly, tsetse, tzetze fly, tzetze,
         glossina]

The Devil's Dictionary (1881-1906):

TZETZE (or TSETSE) FLY, n.  An African insect (_Glossina morsitans_)
whose bite is commonly regarded as nature's most efficacious remedy
for insomnia, though some patients prefer that of the American
novelist (_Mendax interminabilis_).