Cytogenetic studies of the family Lycosidae (Arachnida: Araneae) are scarce. Less than 4% of the described species have been analyzed and the male haploid chromosome numbers ranged from 8+X 1 X 2 to 13+X 1 X 2 . Species formerly classified as Lycosa were the most studied ones. Our aim in this work was to perform a comparative analysis of the meiosis in "Lycosa" erythrognatha Lucas, "Lycosa" pampeana Holmberg and Schizocosa malitiosa (Tullgren). We also compared male and female karyotypes and characterized the heterochromatin of "L." erythrognatha. The males of the three species had 2n = 22, n = 10+X 1 X 2 , all the chromosomes were telocentric and there was generally a single chiasma per bivalent. In "Lycosa" pampeana, which is described cytogenetically for the first time herein, the bivalents and sex chromosomes showed a clustered arrangement at prometaphase I. The comparison of the male/female karyotypes (2n = 22/24) of "Lycosa" erythrognatha revealed that the sex chromosomes were the largest of the complement and that the autosomes decreased gradually in size. The analysis of the amount, composition and distribution of heterochromatin with C-banding and staining with DAPI-and CMA 3 -showed that "Lycosa" erythrognatha had little GC-rich heterochromatin in the pericentromeric region of all chromosomes. In addition, the actual occurrence of the genus Lycosa in the Southern Hemisphere is discussed.

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The spermatogenesis of four species of haplogyne spiders from Argentina is analyzed. Dysdera crocota (Dysderidae) (n = 5 + XO) has holokinetic chromosomes, achiasmatic male meiosis and a post-reductional division of the sex chromosome. Ariadna boesenbergii (Segestriidae) (n = 4 + XO) also possesses holokinetic chromosomes, but meiosis is chiasmatic and the X chromosome divides prereductionally. Kukulcania hibernalis (Filistatidae) (n = 11 + X 1 X 2 O) and Scytodes globida (Scytodidae) (n = 6 + XO) have metacentric and submetacentric chromosomes, chiasmatic meiosis and the sex chromosomes divide pre-reductionally. Kukulcania hibernalis possesses a bimodal karyotype and a particular chromatin coiling during prophase I, while Scytodes globula has striking proximal localization of chiasmata. These results show that Haplogynae present high cytogenetic heterogeneity: species with holokinetic chromosomes as well as species with monocentric chromosomes (metacentric and submetacentric), and species with low diploid numbers, achiasmatic meiosis and proximal chiasma localization.

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