Chromosome studies in stauroderus (an orthopteron)

S. scalaris (Orthoptera, Truxalinae) from Scotland and Siberia has a diploid complex of seventeen chromosomes (six V‐multiples and eleven rods). Each element possesses a polar or proximal granule recognizable throughout all stages of prophase of the first spermatocyte and in all other stages when concentration is not so great as to mask it. In telophase of the first spermatogonial division the polar granules may fuse into a single body or into several irregular bodies (chromoplasts of Eisen and Janssens). By the end of the diatene stage the chromoplast is completely resolved into its component granules which are clearly recognizable as the proximal parts of the rods (ends) and of the multiples (mid‐portions). The accessory chromosome is precocious in its behavior and differential in structure at all stages, but its peculiarities are most marked in metaphase of the first spermatocyte where it becomes a non‐chromatic vesicle with peripheral granules and chromatic core. Each multiple arises from the permanent fusion of two rod elements. They differ from those in other members of the same sub‐family in diakinesis (eight‐strand or octad stage) in that proximal concentration extends almost throughout the multiple.