38 TRESIDENTIAL ADDRESS SECTION C. 



already stated, it ravaged parts of the Cape in the early forties 

 of the last century. From 1847 to 1853 it was prevalent in 

 Natal, so abundant at times, I have been told, that great branches 

 were broken from trees by the sheer weight of resting flyers. 

 A reliable correspondent (A. Meiring, Graaff-Reinet ) has 

 informed me that he saw a huge swarm at Kenhardt in 1869. 

 The years 1842 to 1854, 1862 to 1876, and 1890 to 1909, it should 

 be noted, were periods when the Brown Locust was also present 

 in the country. The Red Locust was observed at Kuruman 

 in 1826 l)y Missionary J. B. Moffat, and he wrote of it as if the 

 natives knew to expect it after the Brown Locust came. 



The Brown Locust usually appears on the wing in great 

 swarms in March or later, and deposits its eggs before winter. 

 The eggs hatch with the first soaking rains of the warm season, 

 generally in October, and the insects become winged about two 

 months later. The swarms then depart, their usual direction 

 of flight varying in different sections of the Union, and being, 

 perhaps, chiefly dependent on the prevailing winds. If the 

 rains come late, the insect develops correspondingly late ; and 

 this fact being well known, late-appearing swarms have been 

 regarded as late-developed swarms when the appearance of the 

 insect indicated, as is often the case in the autumn, that it could 

 not have been long on the wing. Rarely, apparently, do swarms 

 develop both early and late in any one season at one place. It 

 is therefore not surprising that the insect has been regarded as 

 having only one generation in twelve months. Such an opinion 

 is generally held, but conclusive evidence has accrued showing 

 that the insect must have two generations in twelve months 

 whenever it meets with soaking rains in the spring, and again 

 after three to five months. The swarms that depart at mid- 

 summer are not the swarms that come three or more months 

 later. The latter are later developed swarms, and may be, 

 probably often are, the immediate descendants of the midsummer 

 swarms. This condition of aff'airs was suspected in 1907, but 

 was not proved until the 1913-1914 season, when two generations 

 were experienced in an isolated outbreak in midland districts 

 of the Cape Province. A scrutiny of old reports of locust 

 occurrences, in connection with rainfall records in the light that 

 two generations are possible, shows that two generations doubt- 

 less occurred in several years during the last great locust cycle. 

 Eggs are deposited by the first generation about a month after 

 the winged stage is reached, and the hatching may occur within 

 another month. One record states that eggs laid in the middle 

 of January, 1907, hatched within fourteen days. The eggs, as 

 already implied, require moisture for their development. Popular 

 tradition has it that in the absence of adequate moisture and 

 warmth, they may retain their vitality for fourteen years. Tests 

 made by the writer showed that they would hatch after three 

 and a half years, and there is no reason to doubt that suitably 

 preserved eggs would hatch even after a much longer period. 



