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

Abstract Eleven segments are recognized in a comparative study of the abdomens in immature 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 tergum 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 apparent tenth segment of the abdomen is the true eleventh segment. A fusion of the true ninth and tenth segments occurring in the third molt further reduces the number of segments to nine which is the apparent number of segments found in the adult.