A STUDY OF THE FACTOES OF CONTROL. 79 



(Spkccothcrcs flai'ivr ntris) , the leatherhead {Troindorhynchus bucer- 

 oides), the blue jay {Gruucalus mclanops), and the drongo {Chihia 

 hracteaia). The shining starling (Calornis metallica), though nsually 

 considered a fruit-eater, feeds largely upon beetles in season. 



Other birds that are probably just as usefvil are the cuckoo pheasant 

 (Cottropus phasia)U(s) . which normally spends much of its time in the 

 eaneiield; the nightjars or goatsuckers (Eurostopus sp.) ; and the 

 mopokes (Fodargus sp.). All of these insectivorous birds feed upon 

 our pests, but they are seldom seen because of their retiring habits. 



In the vicinity of habitations poultry usually feed greedily upon 

 these pests, so it is advisable to have a few choice feeding-trees where 

 they can be shaken each morning for the fowls to pick up the beetles. 



Predaccous Insects, Mites, and Centipedes also do nuicli to hold our 

 ]>ests in check. The predaceous insects whose habits have been particu- 

 larly studied are several species of Asilid flies, a giant Elaterid beetle, 

 a Pentatomid bug, and the omnivorous ant {Pheidole megacepheda). 



The robber tlies (Asilidaj), so called because they are sometimes 

 destructive to honey-bees, are really valuable insects. They are 

 predaceous at every stage of their life, and it is the larvte of these that 

 are of particular interest to the cane-farmer. The largest and most 

 abundant form in the fields is Promaelius dodeli Bezzi, the larva of which 

 is creamy white, long and tapering at each end, with no feet. These are 

 frequently turned up when ploughing, aud are well-known destroyers 

 of the cane-grubs. 



In our grubby canefields we sometimes also find larvae of a giant 

 Elaterid {Agrypnus meistcrsi Pascoe), which lives primarily upon the 

 grubs. Mr. Dodd kept one of these in confinement for almost two years 

 in a tin of damp earth, during which time it ate over 250 cane-grubs; 

 and still this period apparently represented not more than one-lialf of 

 its larval life. 



The Pentatomid bug {An\iiotea Junnatet Walk.) referred to is 

 commonly seen in the feeding-trees, and on two occasions specimens of 

 this species have been taken with their beaks inserted into cane-beetles, 

 which they paralyse and suck dry. 



The onniivorous ant named above probably does little real damage 

 to our cane-beetles under natural conditions, since these pests are rather 

 too large for them to handle Avhere there is freedom for movement; yet 

 these tiny foes destroy both grubs and beetles while they are in close 

 quarters in the breeding-cages. 



]Mites, too. are usually more troublesome in the breeding-cages than 

 they are in the open fields. It is not uncommon, however, to find them 

 in the fields, especially wJien the grubs are troubled by diseases, &c. An 

 instance of this case was reported from the Isis district in 1909 (42), in 

 which the mites were thought to be the real cause of the mortality among 

 the cane-grul)s. 'Mv. Tryon, however, decided that they were not parasitic, 

 and that the grubs were dying from some other cause (41). 



The large centipede of the tropics is a well-known predator, since 

 it usually congregates among halhtations eating cockroaches, &c. ; yet 

 it is interesting to learn that it sometimes lends a hand in the destruction 

 of cane-grubs, as was discovered by ]\lr. Girault, and later Mr. Jarvi<i 

 {86} had a similar experience with a specimen. 



