Blood volume in the African migratory locust

The blood volumes of locusts were determined by the 14C-carboxyl inulin dilution technique. In each of the last two larval instars the blood volume was low at first, increased sharply at midstage, and remained high until after ecdysis, when it suddenly decreased. In the young adult the blood volume was low until the 8th day, when a gradual rise became evident.Mature locusts generally possessed higher blood volumes than the immature adults. No sign of a diurnal change in blood volume was detected.The isotope gradually disappeared from the blood and became concentrated in the fat body and gonads. No evidence of excretion or metabolism of the 14C-carboxyl inulin was obtained.