VPA 221: Veterinary Entomology and Acarology (1+1)

ABDOMEN

• Shape of abdomen helps to distinguish the sexes
• Female fleas have both ventral and dorsal surfaces convex while in male the dorsal part is more or less flat while the ventral surface is curved
• 10 abdominal segments 8 being easily recognisable
• The 8th ,9th and 10th segments are fused –anal segments
• 9th abdominal segment in the case of both the male and the female bears a pincushion like dorsal plate called the sensilium or  pygidium –this is covered with sensory setae which aids in detection of air currents etc
• The tergum of the 9th abdominal segment in the male forms the paired manubria – a part of the aediagus or the penis
• In females the 7th abdominal segment bears a single spermatheca - this is ‘s’ shaped haing a head , a small  constriction-base, and a tail portion.  This enables species identification in fleas