Histochemical observations of the haemocytes of Locusta migratoria.

Five of the six categories of haemocytes of Locusta migratoria, that is, the plasmatocytes, spherule cells, granulocytes, coagulocytes and oenocytoids, contain conspicuous granules of mucosubstance in their cytoplasm. The mucosubstance has been characterized by using a series of histochemical tests, including Alcian Blue staining at different pH levels and salt concentrations, the periodic acid-Schiff (PAS) test, the high iron diamine test, enzymatic digestions and sequential staining methods. The results indicate that four different mucosubstances occur in a granular form, although not all four are found in every blood cell type. The mucosubstances are a neutral glycoprotein and neuraminidase-resistant, sulphated and non-sulphated sialomucins. The non-sulphated sialomucin occurs in both periodate-reactive and -unreactive forms.