1980] Buschinger, Francoeur, & Fischer —Leptothorax 
5) Karyotype of Leptothorax provancheri 
Nine male pupae from four colonies (colony no. 1: 2 pupae, no. 2: 3 
p., no. 3: 1 p., no. 8: 3 p.) were used for karyotype studies. A total of 67 
metaphases were found with 11 chromosomes each, whereas two had 
the diploid number of 22, and two others had 8 and 21 chromosomes 
respectively. In the latter two cells, a haploid and a diploid one, the 
missing chromosomes presumably have been lost during the prepara¬ 
tion. Thus the haploid number of chromosomes in Leptothorax 
provancheri males is n= 11 (Fig. 3). All chromosomes are metacentric 
or submetacentric. They range continuously in size with the smallest 
of about half the length of the largest. The chromosome number of 
Formicoxenus nitidulus is n=15. Thus a closer relationship between 
L. provancheri and Formicoxenus cannot be demonstrated with a 
comparison of the karyotypes. However, chromosome numbers vary 
often between closely related species among the Leptothoracini. So, 
for example, Harpagoxenus sublaevis has n=20 and Harpagoxenus 
canadensis n=18, Leptothorax muscorum (Nyl.) n=17 and L. 
gredleri Mayr, formerly synonymized with L. muscorum, has n= 11! 
