The polytene chromosomes of species of Eusimulium (Hellichiella) (Diptera: Simuliidae)

Abstract

In an extension of Dunbar's work (R. W. Dunbar. 1967. Can. J. Zool. 45: 377–396) eight species in Hellichiella were examined cytologically on the basis of the banding pattern of salivary gland polytene chromosomes. Hellichiella congareenarum, H. innocens, and H. anatinum were restudied. It was concluded that the sibling distinction between congareenarum and congareenarum 'b' stipulated by Dunbar is not tenable and that anatinum differs from standard by only one inversion (IIS-1). Species studied for the first time are H. rendalense (from Norway), H. latipes (syn. subexcisum from Britain) and H. saccai (from Italy), and the undescribed "Opinaca" sp. (from James Bay, Quebec), and "sp. near dogieli" (from Norway). Diagnostic features are given for each taxon in terms of (i) fixed inversions from standard (congareenarum), (ii) specific sex differential segments, and (iii) inversion polymorphisms. These features are utilized in the construction of an unrooted cytophylogeny.