40 INSECTS AND MAN 



brown locust, Pachytilus sulcicollis, a small insect of a 

 general brown or straw order. The permanent habitat of 

 the brown locust is in the Kalahari Desert and in German 

 South- West Africa, whence winged swarms spread out 

 over Central and Eastern Cape Colony, Orange River 

 Colony, Basutoland, and Southern Rhodesia, from March 

 to July. At certain seasons the general direction of the 

 swarms is south-easterly, at others north-easterly, though 

 the direction of flight seems little affected by winds. 

 Oviposition (fig. 2) takes place about the first week in July, 

 and each female perishes after laying two or three egg- 

 pouches or packets, each containing about forty eggs : the 

 males live a month or two longer. These eggs remain in 

 the ground, where they are laid, till the first rains come, 

 early in October, and two weeks hence, unless the tem- 

 perature has been low, the first hoppers appear. The 

 larvae closely resemble the adults, except that they are 

 wingless; the swarms remain in compact formation, and, 

 from time to time, adjacent swarms amalgamate, till miles 

 of veldt are covered. By day they advance in columns, 

 crossing rivers if necessary by swimming and forming 

 bridges of their massed bodies ; by night they sleep in grass 

 and scrub. After moulting, the larvae become nymphs, 

 and in six to eight weeks the latter become adult, obtain 

 their wings, and immediately fly back to the Kalahari 

 Desert. Sometimes the females lay their eggs in regions, 

 such as certain parts of Cape Colony, where rain only falls 

 every six or seven years; in this event the eggs remain 

 dormant, though fertile, for several years, and, when the 

 rains come eventually, the larvae emerge none the worse for 

 their long developmental period. 



The second South African species is the red locust, 

 Gyrtacanthacris septemfasciata, so called because the newly 

 mature insects are of a reddish-brown colour, whilst in the 

 breeding season the hind wings are of a bright claret hue. 

 This insect is considerably larger than the brown species, 



