The cerebral neurosecretory cells and retrocerebral endocrine complex in several representatives of staphyliniformic beetles (Coleoptera, Staphyliniformia).

The cerebral neurosecretory cells and retrocerebral endocrine complex were histologically studied in 20 species representing 4 families of the series Staphyliniformia (Coleoptera, Polyphaga). In their brains, the neurosecretory cells are clustered in one usually unpaired median group of the pars intercerebralis and in paired dorso-lateral and lateral groups. Up to 5 distinct neurosecretory cell types were found in the pars intercerebralis. In Hydrophilidae, Staphylinidae and in Nicrophorus species (Silphidae), the median group includes generally 20 type I neurosecretory cells and 16 type II neurosecretory cells. In Histeridae and Silphini species, the number of type I and II neurosecretory cells reaches 60-90 each. In staphyliniformic beetles, as in other Coleoptera, the number of type III and V neurosecretory cells is equal to 4. The corpora cardiaca are paired and fused with lateral aorta walls. In Hydrophilidae, Staphylinidae and Silphini, two pairs of the nervi corporis cardiaci innervate the corpora cardiaca. There is only one pair of the nervi corporis cardiaci in Histeridae and Nicrophorus species. The corpora allata join directly the corresponding corpora cardiaca. They contain frequently the neurosecretory products of cerebral neurosecretory cells.