92 



FROGHOPPER BLIGHT OF SUGAR-CANE. 



THE PARASITE COMPLEX. 



In the above pages an outline has been given of the various parasites 

 and hyper-parasites with which the froghopper is associated in the cane 

 fields. In Fig. 19 an attempt has been made to show in diagramatic 

 form the way in which all these animals and fungi are inter-related. In 

 the centre the froghopper is shown and in the first ring round it are all 

 its natural enemies grouped according as they feed on the egg, nymph or 

 adult. In the outermost ring are the hyper-parasites or enemies of the 

 enemies, and in the intermediate ring are shown other hosts or foods of 

 the parasites and hyper-parasites. The arrows indicate that the animal 

 at the feather of the arrow destroys the animal at the tip. 



Pig. 19. 



Fig. 19— Diagram illustrating the Parasite Complex centring round the froghopper. 



A careful study of this diagram will show the extraordinary complexity 

 of the relationships and the great difficulty of deciding whether any 

 jsarticular animal is valuable or undesirable. 



