Chromosomal evidence for sibling species of the malaria vector Anopheles (Cellia) culicifacies Giles.

The ovarian polytene chromosomes of adult Anopheles culicifacies from natural populations in Pakistan, India and Sri Lanka, and from four laboratory colonies (one from Pakistan and three from India) are compared with the published cytological map for this taxon. Two types of X-chromosome exist. One of these is identical with the published map; the other differs by two inversions. No autosome arm rearrangements are detected. A photomap is presented which documents the X-chromosome inversions. Both types of Xs are found in a natural population near New Delhi in the apparent absence of heterozygotes. This is interpreted as evidence for biologically distinct species within the taxon An. culicifacies Giles. The formal taxonomic and practical implications are briefly discussed.