Abstract. An analysis of testicular morphology and spermatogenesis in the Heteroptera species Antiteuchus tripterus (Pentatomidae) revealed that these traits differ from that recorded for other species of the same family. The testes of A. tripterus have only six lobes, while other species of the same family typically have seven lobes, including a compound lobe, i.e., a lobe containing another in its lumen. A study of meiosis and sperm structure in the different lobes of A. tripterus revealed a conventional meiosis in the lobes numbered one to three. In lobe four, however, prophase I spermatocytes exhibit the morphological characteristics of the so called "diffuse" stage and are larger than those in lobes 1-3 in this and the remaining phases of meiosis. Thus, the resulting spermatids are not only larger but also their head is morphologically different. Lobe 5 exhibits characteristics known from other Pentatomidae species such as an uneven distribution of chromatin to the daughter cells, which give rise to cells of different sizes. This lobe forms spermatozoa of different sizes. Lobe 6, contained within lobe 5, differs from it by having larger cells at a stage similar to the so called "diffuse" and spermatid tails with cross divisions, which are not found in other lobes and unreported in the literature.

ABStrACt. Males of Limnogonus aduncus were found to have the sex chromosome system X0 and chromosome number 2n = 23 (22A + X0). Testis cells were stained with lacto-acetic orcein and silver nitrate so that changes in the morphology and degree of staining of the heteropicnotic chromatin and the nucleolar material could be observed during meiosis and spermiogenesis. These structures share the same nuclear position and could be seen until almost the end of spermiogenesis. A chromosome region stained with silver ni-

Summary Some cytogenetical aspects of spermatozoa formation were studied in 9 Coreidae Brazilian species: Anasa bellator, Athaumastus haematicus, Chariesterus armatus, Dallacoris obscura, Dallacoris pictus, Leptoglossus gonagra, Leptoglossus zonatus, Sphictyrtus fasciatus, and Zicca annulata. Similarly to the other species described to date, all the species studied herein showed cystic spermatogenesis, a reddish membrane covering the testes, a X0 sex determining system, a pair of m-chromosomes, intersticial chiasmata in most autosomes, and autosomes dividing reductionally at first meiotic division and equationally in the second 1 while sex chromosomes, divide equationally and reductionally at first and second meiotic division, respectively. In addition, it was observed that the sex chromosome is heteropycnotic at prophase and that heteropycnotic chromosomal material is found in the nuclei at spermiogenesis. In the species studied, the diploid chromosome number ranged from 19 to 25. It was 19 in S. fasciatus (16Aϩ2mϩX0); 21 in A. bellator, A. haematicus, D. obscura, D. pictus, L. gonagra, and L. zonatus (18Aϩ2mϩX0); 23 in Z. annulata (20Aϩ2mϩX0); and 25 in C. armatus (22Aϩ2mϩX0).

ABSTRACT. Although they are of economic importance, there have been few cytogenetic studies of the Gerridae (Heteroptera) in Brazil. We examined spermatogenesis (meiosis and spermiogenesis) and nucleolar behavior in three species of the family Gerridae. Brachymetra albinerva and Halobatopsis platensis were found to have a chromosome complement of 2n = 25 (24A + X0) and Cylindrostethus palmaris 2n = 29 (28A + X0) chromosomes. Fifteen individuals of these species were collected from the reservoir of São José do Rio Preto, SP, using screens and were transported in pots containing water to the laboratory, where cytogenetic preparations were made. The polyploidy nuclei are formed by several heteropyknotic regions; cells in meiotic prophase have a heteropyknotic region that is probably the sex chromosome, and the chromosomes from chiasmata. The spermatids are rounded and have a heteropyknotic region at the periphery of the nucleus; the sperm head is small, with a long tail. Silver impregnation of meiotic cells showed one or more disorganized bodies around the perichromosomal sheath. The round spermatids had two bodies next to each other, but these were elongated; one of the bodies remained in the head and the other migrated to the initial part of the tail at the end of spermagenesis, when the staining was no longer evident. The meiotic cells appear during

The Heteroptera are known for their odour, for being pests or for being disease carriers. However, they are still not extensively studied, perhaps because they form a very large group. Therefore, with the aim of enhancing the knowledge of the morphology of the testes of this insect order, we collected and analysed 18 species of terrestrial Heteroptera from the northwestern part of São Paulo. The analysis of these species revealed some differences between the testicles of these species, including their shape (elongated, oval, round or pecten), the morphology of the testicular lobes (elongated and paired side by side or united in a single region), the colours of the peritoneal sheath that surrounds the lobes (red, orange, yellow or translucent), and the number of testicular lobes (one, two, four, five, six or seven). Because the aspects analysed were highly variable, our study suggests a need for further analysis of Heteropteran testicular morphological differences.