The origin of the present paper is based on two large collections of Odonata, recently made in Trinidad. The first one is my own collection brought home from my stay in the island in July and August 1929, containing several hundreds of specimens from different localities. The second one is that of Dr. E. M. WALKER in Toronto Ontario, generously sent to me for examination. It also contains many hundreds of individuals, collected in the island in Sangre Grande by G. BELMONTES in 1930 and 1931. Lateron in 1931 and '32 two sendings of the same collector were received for my collection, by which it was enlarged by some rare and not yet represented species. It may be interesting to know that duplicates of most of the species in my collection are handed over to 's Rijks Museum van Natuurlijke Historie at Leiden. In the following account I have attempted to gather up all notes and indications of all Odonata which have been recorded from Trinidad, or which are otherwise known to me to occur in this country. Therefore it must be understood as a foundation, by which future discoveries will prove to be facilitated and as it makes our view on the fauna of this island more complete, a useful contribution to our poor knowledge of the Lesser Antilles. Attention must be called to the important results of E. B. WILLIAMSON, who visited the island in 1912 during a collecting trip in the West Indies with his father the late L. A. WILLIAMSON and B. J. RAINEY. A rich collection of Odonata was brought home by these gentlemen, of which since many particularities have been recorded. The first contribution to the Odonate-fauna of Trinidad was furnished by J. H. HART in the