Entomological investigations in the tropics usually entail a certain amount of difficulties not experienced in temperate regions, and it is often necessary to devise various kinds of apparatus to overcome these. The breeding cage described here was devised by myself as the result of a number of difficulties experienced in breeding experiments. Cages of this type have been in constant use in this laboratory for the past four years and have been found to meet almost every requirement. The ease with which they are constructed, together with the possibility of varying their size to suit one’s needs, as well as their portability, are all highly commendable features.