THE FAUNA OF THE CACAO FIELD 111 



be readily destroyed in several ways, viz., by sulphur 

 fumes driven in by a centrifugal fan or bellows ; by 

 pouring coal tar into their nests ; by use of bi-sulphide of 

 carbon as a fumigator or explosive in their tunnels, or by 

 puddling the whole of the nest into a paste with water. 

 The attack of a colony of this insect is very insidious, as 

 the insects generally work at night, remaining quiescent 

 during the day ; and nests may develop in the neighbour- 

 hood of an estate to a large size before being discovered 

 by the night raid which does damage. They should be 

 treated like fires ; when discovered " put them out " of 

 existence. Where present, these ants are terrible pests 

 to the cultivator, and those who have had no experience 

 with them can hardly realise the amount of damage they 

 can do. Atta cephalotes, or the " house builder," is the 

 most voracious. The members of its nest consist of some 

 eight forms of the insect, respectively : (1) king ; (2) queen ; 

 (3) soldier ; (4) worker major ; (5) worker minor ; (6) 

 nurse major; (7) nurse minor; and (8) nurse minimus 

 (illustration in the latest edition of the " Cambridge 

 Natural History," by Professor Sharp, from Trinidad 

 material). Atta octospinosa, Forell, is a less warlike species, 

 and is chiefly found in the vicinity of dwellings, while 

 A. cephalotes ranges the forest and cultivated lands as well 

 as gardens. The soldier form of the insect is able to make 

 a severe attack upon any one who inadvertently steps 

 upon a well-guarded nest, its mandibles being able to 

 pierce easily through a thick woollen sock. In Trinidad 

 a law has been passed to enable control to be maintained 

 over their spread, but they are still ubiquitous. In the 

 swarming season the queens fly abroad, each individual 

 being capable of starting a new nest alone and unaided, 

 and constant watch has therefore to be kept for the appear- 

 ance of new nests, the detection and destruction of which 

 is no small item in the annual expense of a cacao estate. 

 These insects are among the most destructive pests to be 

 dealt with by the planter. 



No. 2. Ants {Pormicidce). Many species are believed 



