The collection and study of tropical insects now heing undertaken in connection with medical and other researches has resulted in the publication of two or three very useful leaflets of instructions as to how to catch and send home specimens of blood-sucking and parasitic insects. These leaflets are intended for collectors who will send home their specimens soon after they have caught them: when this is impossible, when specimens have to be carted from place to place and housed, it may be, in very unsuitable quarters, it becomes important to use only the best methods for preserving them in good condition, and the best methods can be arrived at only by combining the experience of collectors in different countries.