458 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 3 



Non-fatal multiple superparasitism involving several individuals — 

 1 example. 



Combined simple ecto- and multiple endoparasitism (non-fatal) — 

 7 examples. 



Cannibal superparasitism with one survivor ■ — 4 examples. 



Mixed superparasitism involving only two individuals with one 

 survivor — 142 examples. 



Mixed superparasitism involving several individuals with one sur- 

 vivor — 7 examples. 



Combined simple ecto- and endoparasitism with one survivor — 3 

 examples. 



Fatal cannibal superparasitism — 34 examples. 



Fatal mixed superparasitism involving two individuals — 102 

 examples. 



Fatal mixed superparasitism involving several individuals — 54 

 examples. 



Combined simple ecto- and endoparasitism (fatal) — 9 examples. 



Total non-fatal superparasitism — 16 examples. 



Total superparasitism with one survivor — 156 examples. 



Total fatal superparasitism — 199 examples. 



Predation by larvae upon primary parasites — 21 examples. 

 Predation by larvae upon superparasites — 2 examples. 

 Predation bj^ adults upon primary parasites — 10 examples. 



A superficial study of the examples given would perhaps give the 

 idea that superparasitism is a serious drawback to control by para- 

 sites. It must not be forgotten that the many thousands of examples 

 of pure simple parasitism have been omitted from the discussion. 

 The writer's observations upon this most interesting phenomenon are 

 that superparasitism seldom if ever occurs until the percentage of 

 parasitism has become comparatively high. From the point where 

 superparasitism does begin, however, it very rapidly acts as a check 

 upon parasite increase until it almost completely stops the control 

 at 75 per cent. Owing to the many other elements of weevil control 

 it is seldom possible for parasitism to reach much above 45 or 50 per 

 cent oj the total number of weevils in the field. The other factors may 

 be counted upon to average about 50 per cent of the total. With 

 very favorable conditions the parasites sometimes reach as many as 

 75 per cent of the weevils. 



