THE FOUR-WINGED PARASITES 181 



other brood of parasites. Or they both may die from lack 

 of food. 



Mr. Fiske has applied the term superparasitism to this 

 excessive parasitism of primary hosts. He classifies the 

 various conditions that may exist as follows : 



I. One parasite lives ; the other dies. 



(a) The survivor preys upon the other as an acci- 

 dental secondary parasite. Of common occur- 

 rence. 



(b) The survivor destroys the other by bringing 

 about the premature death of the host and may 

 or may not devour it incidentally. Of common 

 occurrence. 



II. Both parasites live. 



(c) Neither is the worse for the circumstances. 

 Very rare. 



(d) One or both are so seriously weakened and 

 stunted as to bring about a material reduction 

 in their capacity for reproduction. Common. 



III. Neither parasite survives. 



(i) This may be brought about through the prema- 

 ture death of the host through excessive para- 

 sitism (commonly) ; or 



(/) Through the inability of either parasite to 

 complete its transformations on the limited 

 supply of food. Common. 



If you will stop to think what must be constantly hap- 

 pening in the world of insects on account of the existence 

 of these many primary, secondary, and other parasites, you 

 will see that the relations between them must be very com- 

 plicated. A caterpillar that is a great crop pest becomes 

 abundant. Its primary parasites soon become abundant 



