Eggs of 11 forensically important calliphorid species belonging to six
genera were studied with SEM for useful diagnostic characters. Identi
fication was confounded by the following three factors: (1) variabilit
y within and among populations of the same species, (2) similarities a
mong some congeneric species, and (3) similarities between some specie
s of different genera. Reliable separation based on morphology should
take into account relevant aspects of blow fly biology as it is affect
ed by locality, climate, season, and weather.