RESULTS OF AGE-GROUPING DISSECTIONS ON FOUR SPECIES OF ANOPHELES FROM SOUTHERN GHANA.

The entomological survey during the preparatory phase of the Malaria Eradication Pilot Project in Ghana included a programme of age-grouping dissections on the local malaria vectors. After an initial year spent on the older methods, some 1700 female mosquitos were dissected following Detinova's techniques. These latter results, though limited to a division of the nulliparous from the parous, are examined in detail to discover what they reveal of the age-structure of the anopheline populations concerned.Analysis of the proportion parous of A. gambiae populations showed, inter alia, that they fluctuated considerably in age make-up from week to week, even though appearing fairly stable over longer periods. The risk of calculating survival probabilities without an exact knowledge of the structure of the nulliparous population is also illustrated, and it is suggested that such estimations should be restricted to an expression of the proportion parous.