June, '10] HOWARD: AFRICAN LOCUST PROBLEM 263 



whole continent ; whatever may be the facts concerning North and 

 East African locusts those of South Africa, so far as we have been 

 able to ascertain have no connection therewith. 



I shall avoid the points still open to discussion and state briefly the 

 main facts about the migrations and life history of these two locusts. 



The most destructive and the most difficult to combat is the Brown 

 Locust (Pachytyhis sulcicollis). It is a small locust of quite a uni- 

 form brown or dark straw color. Its permanent summer quarter 

 (January to March or until July) seems to be somewhere in the 

 Kalahari desert and German South West Africa. From here they 

 begin to spread out in March, but sometimes not until July, the 

 winged swarms eventually covering an area w^hich may include, Cen- 

 tral and Eastern Cape Colony, Orange Free State, Basutoland and 

 most of Southern Ehodesia. Apparently they seldom cross to the 

 North of the Zambesi River, and only at the height of the cycle will 

 they cover the entire area mentioned above. So far as we can ascer- 

 tain their flight is affected very little by winds, although certain sea- 

 sons, for some reason, the bulk of the swarms turn to the south east 

 from the Kalahari and during other seasons to the north east. 



By about the first of July these winged swarms begin to oviposit. 

 Each female deposits two or three pods of eggs of about 40 eggs each, 

 and then perishes. Males may survive one or two months longer. 

 The eggs lie in the ground until the first rains, which usually begin 

 about the first of October. In two weeks after the rains the first hop- 

 pers appear, providing the atmosphere has been warm enough. Many 

 variations as to time of hatching occur, owing to variations in the time 

 of the beginning of rains and owing to the intensity of the first rains 

 or the lack of proper temperature. I have seen eggs hatching only 

 in the following February and March and eggs deposited in the areas 

 of Cape Colony where rain only occurs once in 6 or 7 years, will 

 remain dormant several years and still hatch. I have kept eggs my- 

 self two years; they hatching at the end of that period when they 

 w'ere subjected to proper conditions, and I believe that the Cape 

 Entomologist has secured hatchings after a lapse of five years. 



From 6 to 8 weeks are necessary for the growth of the nymphs, at 

 the end of which time they obtain their wings and immediately fly 

 toward the Kalahari. From the Transvaal they follow almost a bee- 

 line to the south west and this is true of Rhodesia, while from the 

 Orange Free State they go westward. 



The voetgangers of the Brown Locust remain from the very first in 

 very compact swarms, sleeping in masses in grass and scrub during 

 the night and moving in massed columns during the dav. Swarms 



