An Interpretation of the Haemocyte Complex in a Stonefly, Acroneuria arenosa Pictet (Plecoptera: Pteronarcidae)

Abstract

The haemocytes of adults of the stonefly, Acroneuria arenosa Pictet, are described and figured as they appear in vivo in the wings and as fixed and stained elements in blood films prepared in four different ways. The adequacy of the blood films is judged by comparing the haemocytes there with those in vivo, and the cell complex is interpreted from both aspects. Four categories of haemocytes, the prohaemocytes, plasmatocytes, granular haemocytes, and hyaline haemocytes, are denoted and characterized within these visual limits. The validity of one category, the hyaline haemocytes, is questioned on the basis of cell counts and cell morphology but is tentatively retained. Variations in the haemocyte complex during the adult life is considered. The progressive decrease in relative numbers of circulating plasmatocytes with age is shown to be due to their adherence to the walls of wing veins and presumably to other tissues within the body.