INTRODUCTION During 1923 and 1924 the writer spent fifteen months in Colombia, being engaged as Entomologist and Supervising Inspector for the Campaign against yellow fever that was being carried on there at that time. The mosquito control work and other duties in connection with this Campaign necessitated considerable travel throughout various parts of the Republic. This afforded an opportunity for collecting specimens of some of the insects and other arthropods affecting man and animals and also for making a few observations on the distribution of the most important varieties. Although the yellow fever work prevented as much time being devoted to this pursuit as would have been necessary to obtain a large collection, a number of the more common blood sucking insects and also a few new species were secured. An annotated list of these is presented in the following article.