Haemocytes increased gradually from the first instar to late fifth instar larvae
of the cut worm, Agrotis ypsilon.The haemocyte number declined during the prepupal
stage. Ligation and decapitation decreased the haemocyte number in the posterior
part of the larvae. Injection of brain homogenate either from early last Instar larvae of
A. ypsiJon or nymphs of Schistocerca gregarfa into decapitated larvae, caused
increase in haemocyte count. Injection of 20-hydroxyecdysone into the posterior half
of thorax ligated larvae caused a significant increase in haemocytes, while application
of juvenile hormone alone had no effect.