Generica 83: 275-287, 199 I. 0 199 I liiu~~er Academic Publishers. Printed in the Netherlands. 275 Allozymic characterization of Sardinian Bacillus rossius (Rossi) and B. atticus Brunner (Insecta Phasmatodea) B. Mantovani & V. Scali Dipartimento di Biologia Evoluzionistica Sperimentale, Universitri di Bologna, Via S. Giacomo 9,40126 Bologna, Italia Received 9 August 1990 Accepted in revised form 1 I December 1990 Abstract The aliozymic characterization of newly discovered populations ofB. attieus and B. rossius is given. Most Sardinian B. rossius demes belong to the subspecies B, r. rossius, Southeastern populations are B. r. redtenbacheri, while the central ones appear to be intermediate. Like all Italian B. atticus, also Sardinian demes belong to B. a. cuprai. The presence of B. atticus alleles in syntopic B. rossius populations is explained through gene introgression due to past hybridization events between the two taxa. Introduction reproductive biology. Among known taxa (Scali & Mantovani, 1989) the genus includes (Fig. 1): (1) the Distributional, ecological and morphological charac- teristics together with karyological and genetic differ- entiations of the holomediteranean genus Bacillus are currently under careful investigation with the aim of clarifying its taxonomy, phyletic relationships and bisexual B. rossius (Rossi), diploid (2n=36 in the female and 2n=35 in the male) also with many facultatively parthenogenetic demes. The taxon spreads over most of the Western Mediterranean basin where it is differentiated into at least 8 sub- I--- B mm 61 - Fi.q. 1. Map of the Mediterranean basin showing the distribution of Baci//us rossius and 3. atticus subspecies. n : 6. r. tripolitanus A: 0: 3. I tripolitanus B, E B. r. iobipes; I]: B. r. montaientii; IZ: B. r. medeae; El: B. r. cataiauniae; B: bisexual B. r. rossius; 1: unisexual B. r. rossius; a: bisexual B. r. redtenbacheri: AI unisexual B. r. redtenbacheri; 0: B. a. atticus; @: B. a. baccettii; CD: B. a. mullen’; l : B. a. caprai.