chromomere is A small, bead-like structure that is visible in a chromosome during prophase of meiosis and mitosis, when it is relatively uncoiled (in particular at the leptotene and zygotene stages of meiosis). In polytene chromosomes, the chromomeres lie in parallel, giving the chromosome its banded appearance. Chromomeres in corresponding positions on homologous chromosomes pair during meiosis in many organisms ....
A chromomere is a serially aligned beadlike granule of concentrated chromatin that constitutes a chromosome during the early phases of cell division.
i must confess that I am not particularly familiar with grasshopper gametogenesis, however, since they progress through meiosis in a similar fashion as mammals, I would assume that the chromomeres would first become visible toward the end of leptonema or at the beginning of zygonema.
Hope that helps!