Figure 4.

(A) Evolution of the vagina and the left spicule in the five species of Dipetalonema spp. sensu stricto, known from platyrhinian monkeys: the proximal lumen of the vagina is a straight tube in the primitive species D. caudispina; it will become coiled to control the delivery of microfilariae, the maximum of complexity being reached in D. graciliformis. In parallel, the distal lamina of the left spicule evolves from a thick short part to a long and thin one, capable of penetrating deep into the complex vagina (in 57). (B) Hypothetic representation of the mating in filariae: the male grasps with its posterior region the female at level of the vulva, which is situated in the anterior part; area rugosa on the ventral aspect of the male and a body swelling of the female are presented (in 56). (C) A body swelling of Mansonella (Tetrapetalonema) mariae Petit, Bain & Roussilhon, 1985 due to the presence of a giant pseudocoelomocyte (transverse section) (in 56). (D) Caudal region of Brugia malayi, Indian strain characterized with the numerous cuticular bosses, beginning on the right side (in 55).