The segmentation of the abdomen of Lipeurus heterographus Nitzsch (Mallophaga)

Eleven segments are recognised in a comparitive study of the abdomen in imiture and adult instars of Lipeurus heterographus Nitzsch. The abdomen of the first instar appears ten segmented but with the apparent first segment twice as long as any one of the others and with two transverse rows of hairs on the turgum while the other abdominal segments have but one. This indicates that the apparent first segment is the true first and second abdominal segments which have fused. The apperent tenth segment of the abdomen is the true eleventh segment. A fusion of the true ninth and tenth segments occuring in the third moult further reduces the number of segments to nine which is the apparent number of segments in the adult.