PRESIDENTIAL ADDRESS SECTION C. 43 



State and the Cape. After that the plague subsided, and, as 

 already explained, the cycle is regarded as having finished with 

 the 1909 season. But another series of dry years began at 

 once to creep over much of the country, and 191 2 in particular 

 was a drought year practically over the whole summer rainfall 

 area of the Union A part of the Cape Province centring about 

 Doornberg, in the Middelburg district, a region to which locusts 

 are partial, received only about one-third its average rainfall in 

 this year, but early in 1913 was favoured with good rains. At 

 once locusts appeared here unexpectedly. Farther north, in 

 the Fauresmith and surrounding districts, the drought continued 

 until the past October and November ; but when it finally broke, 

 there locusts appeared also. The rains of the past summer, as 

 intimated a few moments ago, were exceptionally good over 

 much of the country, and general trouble with locusts may now 

 be imminent again, as I stated in introducing this address. Yet 

 the area in which we know them to have shown themselves this 

 year, although its limits embrace nearly 100,000 square miles, 

 is only a small portion of the great region that I regard as the 

 probably permanent habitat of the species ; and perhaps it is a 

 relatively inconsequential portion in so far as excessive multi- 

 plication is concerned. F'erhaps only when conditions are 

 generally favourable for the breeding up of the pest over much 

 of the enormous stretch of arid territory from Gordonia north 

 beyond Lake N'gami is there danger of those mighty swarms 

 developing that from time to time spread over so much of the 

 country ; and concerning the conditions that apply to locusts in 

 that territory we are almost completely ignorant. My impression 

 is that it is an immense dreary thirstland, where swarms of 

 great magnitude might easily be produced and perish in the 

 fulness of time without once having come under the observation 

 of civilized man. Swarms are recorded to have been seen near 

 Lake N'gami in August, 1889 (Sander: Die Wanderheusch- 

 recken, p. 22). that is, eighteen months before locusts were seen 

 in the Union in the 1890- 1909 cycle; and the Red Locust was 

 reported there in 1893 and at Palapye in October, 1894 (Cape 

 Agricultural Journal. 9, 331), whereas it was not found m 

 Griqualand West until early in 1895. The cjuery naturally 

 arises : Does a cyclical change come down from the northward 

 brino-ins locusts in its wake? Here again 1 look to students 

 of climate for assistance. 



The sudden appearance of the Brown Locust in large 

 numbers after a drought, without there having been any invading 

 parent locusts, is explained, I think, by the fact that eggs of this 

 species preserve their vitality for years in the absence of adequate 

 moisture for their development. I imagine that eggs accumulate 

 during a series of dry years, and are all hatched under the 

 influence of a soaking general rain. The bird and insect enemies 

 of locusts would naturally be relatively scarce when the general 

 hatching occurred, and thus the locusts, with plenty of food about 



