ABSTRACT
The inorganic cations in the haemolymph of Antheræa pernyi larvae and pupae were analysed by flame photometry.
Synthetic media based on these analyses were compared with haemolymph in their effects on the muscle action potential and on the response of the dorsal muscle receptors to a standard stretch.
The best match with haemolymph was obtained in all cases with concentrations of divalent cations considerably below the values found by flame photometric analysis. Binding to haemolymph proteins is probably not the major factor responsible for lowering the ionic activities of calcium and magnesium.
The role of magnesium in neuromuscular transmission is discussed. It is concluded that in phytophagous Lepidoptera this ion may carry a proportion of the muscle action current.
I am grateful to my supervisor, Prof. G. M. Hughes, for guidance and encouragement during this work, and to the D.S.I.R. for financial support in the form of a research studentship.
