Fig. 1

Meiosis in Panstrongylus lutzi males (Giemsa staining). 2n = 20A+ X₁X₂X₃Y a Zygotene with four heteropycnotic chromocenters (arrow). b Pachytene with a single chromocenter formed by sex chromosomes (arrow). c Late Diplotene. Each one of the ten bivalents showed one chiasma while the sex chromosomes appeared close associated (arrow) d Metaphase I showing ten bivalents, three X chromosomes (X₁X₂X₃) (arrowheads) and Y chromosome (arrow). The dashed circle indicates two major bivalents. e Anaphase I. Equational division of sex chromosomes indicating X₁X₂X₃ chromosomes (arrowheads) and Y chromosome (arrow). f Metaphase II with ten half-bivalents and the four sex chromosomes forming a pseudotetravalent (arrow). Scale-bars: 5 μm