98. When I arrived on Uvea in February the island was suffering its annual plagues of mosquitoes. They made life uncomfortable in the day and necessitated all skinning or writing being done under nets, but at night simply became impossible, thick clouds of them simply making the night one long hideous "ping". Walking about one could feel them bumping into ones face in scores, and to wave ones arm was to strike dozens. In and about the swamps they were thick day and night but not in the clouds such as they were from dusk (5:30 P.M.) onwards till after daylight. In February and March it was very noticeable how plentiful Collocalia leucopygia spodopygia was over the swamps and from 5:30 onwards the birds were to be seen in hundreds and even thousands hawking over the swamps. When the mosquitoes dis- appeared or rather the clouds of them, some always being present, Collocalia simply vanished nor did they appear in other areas of the island, in fact they became scarce all over the island. The following notes on dates were made at the time. Up to and before 17th of April numerous notes speak of the abundance of the species everywhere and especi- ally in the swamps. During the week from the 17th to 23rd they still seemed common, but decreasing slightly especially over the swamps and during this time the mosquitoes began to decrease. (Collocalia feeds on them as I have found them in the beaks of shot birds.) I began to take closer note and recorded these in my casual log and on the 30th the facts had assumed sufficient significance to warrant close noting in the field book and notes were kept daily closely after that.