1S0 SOME ETHIOPIAN REPTILES, FISHES, AND INVERTEBRATES 



its grip, whilst the sticky exudation is poured out copiously from the gland in the 

 head. If no enemy can be found, the soldiers gradually retreat into the nest, and 

 the workers bring up earth and repair the breach, but the soldiei's continue to line 

 the exposed galleries with their heads directed outward ready to meet a further 

 assault. Except by acting as escort to foraging-parties, the soldiers seem to take 

 no part in procuring food for the community, and the extreme modification of 

 their mouth appears to prevent them feeding on hard substances such as wood. 

 The individuals destined to mature sexual characters are distinguishable in early 

 life by their larger size and the possession of small pads which later develop into 

 wings. These so-called nymphs with wing-pads may be found in some nests at 

 almost any season of the year, but are most common in spring, at which time 

 batches of twenty or thirty may often be found in small chambers within the nest. 

 They do not seem to be provided with fungus-comb as a rule, and it seems 

 probable that instead of eating fungus, they are fed in a special manner, either 

 by food digested and disgorged by the workers or in some other manner. Just 

 before the rains begin, these nymphs attain the perfect state, and, on the occur- 

 rence of the first heavy shower, issue out of the nest in swarms. Comparatively 

 very few escape the numerous enemies which prey on them the moment they 

 emerge from the nest. Ants, lizards, and birds catch them before they have time 

 to take to flight, and, even in the air, birds, bats, and dragonflies pursue them 

 relentlessly. The few pairs which find a suitable site, usually in a crack or 

 cranny in the ground, commence the foundation of a new nest by preparing a 

 small rounded chamber just large enough to contain both ; this being done by 

 excavating the earth with their mouths and carrying it outside. The female 

 then settles down to the business of laying eggs, to which her future existence 

 is devoted. As the nest grows, the body of the female swells until the 

 brown horny plates which at first formed her back become merely little islands 

 separated by an expanse of white skin ; and ultimately she develops into a 

 monstrous, unwieldy, grub-like animal, incapable of walking, and, in fact, a mere 

 pulsating mass of eggs. How long it takes for the female to assume this 

 monstrous shape is not known, but it is probably not less than two years. A 

 female taken from a mound and placed under as natm-al conditions as possible 

 was found to have laid 359 eggs in fifteen minutes, a 1'ate of oviposition which 

 works out roughly at 34,000 in one day; the extrusion of the eggs being ap- 

 parently an involuntary action. The growth of a nest-mound is very slow at 

 first, and it is probably not until the second year of its existence that it becomes 

 noticeable above ground. By this time its population has become very numerous 

 and extension proceeds more rapidly. In some cases the building of a mound 

 above ground-level is due largely to the necessity for disposal of the earth 

 excavated below ground in extending the cavity which contains the nest, and 

 the pinnacles of the mound form a kind of scaffolding around the mouths 

 of the galleries up which the excavated material is brought. In other cases, 

 however, these pinnacles are left open, and seem to act as ventilating shafts. 

 The particular shape of the mound varies considerably, and is usually character- 

 istic of each species. 



Locusts and grasshoppers of various kinds abound in Africa and inflict great 



