Abstract
There have now been described some fourteen hundred species of Tabanidæ, of which, according to Surcouf (1924), more than a hundred are European. Biological studies of the family have by no means kept pace with those of its taxonomy, and there is available comparatively little information regarding the post-embryonic development of individual species.Examination of the literature showed that none of the European species had been investigated with any degree of detail, and it was with the intention of supplying at least part of this want that the present study was undertaken in 1930. Because of its relative abundance from June to August in rural districts of Scotland, the common cleg,Hœmatopota pluvialis, L., was the species first chosen. The interest of this choice was considerably increased by the relisation that the biology of no species of Hœmatopota had previously been submitted to careful examination either in Europe or elsewhere.