The termite Macrotermes subhyalinus (Rambur) builds large earthen mounds of many different types, two of which are described in detail here. As far as is known at present, the two types occur in different areas. The main difference is in the ventilation system. In one, the Bissel type, there are many holes connected up inside the mound in such a way that external air is drawn through the passages and cools the interior of the mound. The other, the Marigat type, has only one large opening raised to a considerable height above the ground so that air is drawn out at the top, and drawn in from the surrounding soil through underground foraging passages.