none Some biological parameters for a strain of Aphidius ervi Haliday from Southern Italy, parasitizing Acyrthosiphon pisum (Harris) on alfalfa are here reported. Developmental rates obtained at different temperatures allowed to assess a lower developmental threshold of 6.01 degree C and a thermal contant of 197.24 "day-degrees". The longevity attained to its maxmium ( hivin x = 17.5) when females were held at 15 degree C and fed with a water and honey solution. The mimimal longevity ( hivin x = 2.63) was registered for unfed females at 20 degree C. Females fed with a water and honey solution and held at 20 degree C lived about 4 days more than males. When only aphid honeydew was available a longevity increase ( hivin x = 6.3) was registered in respect to starvation. Fertility, as well as longevity, were affected by temperature and food. Total fertility, assessed in terms of mummy production, was highest for females held at 15 degree C and supplied with a water and honey solution (403.16), whereas it reached the minimal value for unfed females held at 20 degree C (168.12).