22 



TABLE III. 



NUMBER OF Endothia parasitica SPORES DISLODGED FBOM THE 

 FEET AND BODY OF Leptostylus macula BY ITS OWN 

 MOVEMENTS. 



Insect number. 



No. 



of Endothia parasitica spores 

 obtained in the cultures. 



No. 



of Endothia parasitica spores 

 obtained from the vials. 



63 





200 





11 



64 





8.538 





85 



66 





100 





3 



A comparison of the results from the insects with those 

 from birds tested in a somewhat similar manner ( 21) shows 

 that the birds carried a larger number of spores of the blight 

 fungus. But it must be remembered that the surface area of 

 the body of the insects is but a small fraction of that of the 

 parts of the birds tested — the head, bill, feet, wing, and tail 

 feathers, — and these latter also offer better opportunities for 

 the lodgment of spores than the smoother bodies of many 

 insects, such as ants. The maximum number of spores of the 

 blight fungus obtained from a single bird was 757,074 not. much 

 more than twice the maximum, 336,960, obtained from a single 

 insect. In proportion to size, therefore, insects may carry a 

 much larger number of spores of Endothia parasitica than 

 birds. Although the insects probably do not carry the spores 

 to as great distances as birds, especially migratory birds, they 

 can nevertheless carry large enough numbers of spores to be 

 important agents in spreading the blight locally. 



In the work on birds as carriers (21) it was found that the 

 highest numbers of spores of the blight fungus were obtained 

 two to four days after a rain, and that the birds were carrying 

 pycnospores only. Not a sufficient number of collections of 

 insects was made to get any definite relation of the number of 

 spores carried to rain periods. It may be stated, however, that 

 nearly all of the insects brought in from the field were taken 

 four days or more after a rain, for May and June, 1913, were 

 rather dry months. Since the insects were carrying pycno- 

 spores almost exclusively we believe that they too will be found 



