NATURAL HISTORY OF SOUTH AFRICA 



Wise Nature, knowing that the insect army in 

 richly cultivated fields is at times likely to gain' the 

 upper hand in spite of the constant onslaughts of 

 birds during the daylight hours, has provided another 

 powerful check. 



Moths fly by night and lay thousands and tens of 

 thousands of eggs during the hours of darkness. One 

 female moth, therefore, is capable of producing a 

 small army of caterpillars. Every moth destroyed 

 before it succeeds in depositing its eggs is equal to 

 killing five hundred or a thousand caterpillars. 



The night jar {Caprimulgus), variously known as 

 the night hawk, goat-sucker, nachtuil, has been 

 specially evolved by the Creator for the purpose of 

 preying on insects which fly by night. Emerging 

 from its leafy retreat at dusk, it is on the hunt the 

 entire night, and its labours do not cease until dawn. 

 The number of insect pests it destroys is enormous. 

 When flying insects are in insufficient numbers to 

 satisfy its needs, it seeks others on the roads, pathways, 

 and other bare spots, surprising them while they are in 

 the act of travelling to seek more succulent vegetation, 

 or a suitable place in which to hide and change into the 

 chrysalis state preparatory to issuing forth as fully- 

 developed winged insects. 



From an analysis of the stomachs of a number of 

 night jars, the following one may be taken as an average 

 example : — 



80 moths; 46 beetles; 8 caterpillars; 21 insects 

 of various species. 



Taking half the moths and beetles to be females, 

 68 



