Synopsis of the dragonflies (Odonata) of Ceylon

Thanks to the important work done by F. F. Laidlaw and F. C. Fraser on the Odonata of India and adjacent countries, we are now tolerably well informed about the occurrence and ecology of these insects in this part of the world. In his recent paper on the derivation of the Ceylonese Odonata, Laidlaw (1951) has given a very useful analysis of the dragonflies of this island. For details concerning the composition and the origin of the dragonfly fauna, the reader is therefore invited to consult Dr. Laidlaw's interesting account. Consequently, there is no need to comment in great detail upon the collection dealt with in this paper, although in the annotated list that follows I have thought it worth while to include all species known from Ceylon, so as to make the survey up to date. The present report is based on a collection of Odonata made in 1953, on an expedition to Ceylon by Dr. Fred Keiser, of the Naturhistorisches Museum at Basle, Switzerland. The insects were caught in a great many localities scattered all over the island, including a number of places situated in the northern provinces and the southern peripheral districts of the island, where little or no dragonfly-hunting had been done in the past. Dr. Keiser's collection means a welcome addition to our knowledge of the regional fauna. There are many hundred specimens, and although very few Platystictidae and Gomphidae are included, the collection in other respects is a fairly representative one, comprising 65 species in all, or about 60% of the total. Apart from two species that appear to be new to science, it contains also a few little known forms, which are commented upon below. In the present paper 107 species are recorded as occurring in Ceylon,