The fact that the swallowing muscles have not yet been described for any member of the order Odonata was first brought to the writer's attention in the course of studies on the mechanism of moulting and hatching of I. verticalis. A previous writer on that subject had described an Odonate nymph as swallowing water without the use of any stomodeal dilator muscles, which he had assumed were absent.

The following notes are written to place on record certain authentic records of tropical species taken in the southern United States. Most of these species are not at present recorded in the North American lists. Unless otherwise stated all specimens are in the author's collection.

During the course of investigation of the mayfly fauna in streams in Ontario and Quebec it became apparent that many of the nymphs of the Baetinae are not known although the adults of most have been named. A few nymphs are described in scattered papers in the literature and a key has been made for some Baetis and Pseudocloeon (McDunnough 1932, 1932a) which satisfactorily separates groups within these genera. It would seem that in work on streams in the future these small mayflies would become increasingly important because of their abundance and wide distribution.