The observations herein recorded were carried out on a portion of the foreshore and of the low-lying front-lands in the vicinity of Georgetown, British Guiana, during the months of January, 1925, and July and August, 1926. The results obtained appear to be of sufficient interest to warrant their being placed on record as throwing further light on the breeding-habits of two important mosquitos of this Colony, namely, Anopheles tarsimaculatus, Goeldi, and Aëdes taeniorhynchus, Wied.

The principal area in which the investigations were carried out is situated to the north of Kitty Village outside of the Sea Wall and is bounded on the south by that wall, on the west by the Kitty Groyne, and on the east by another groyne (Case Groyne) erected a few years ago as part of the sea-defences. The area measures roughly from east to west about 700 yards and from north to south about 200 yards at its greatest width, and about 60 yards at its narrowest part, these being situated at the western and eastern boundaries respectively. The accompanying sketch-map gives a general plan of the area. The places from which mosquito larvae were collected are indicated on the plan, Anopheles by black spots, Aëdes by concentric rings.