[Experimental interspecific hybridization in fleas of the genus Nosopsyllus (Siphonaptera: Ceratophyllidae)]

Experimental interspecific hybridization between males and females of Nosopsyllus fasciatus and N. mokrzeckyi was carried out. Most abundant progeny was obtained after hybridization between N. fasciatus females and N. mokrzeckyi males. Hybrid descendants inherited, in general, the characters of the maternal species and in less number the paternal characters and those of both parents. The fecundity of hybrid progeny of N. fasciatus females and N. mokrzeckyi males in two generations was studied. A conclusion is made concerning close affinity of the species and their relative evolutionary youth.