27 



SUMMARY AND CONCLUSIONS. 



1. Each insect tested was placed in a flask containing 100 

 cc. of sterile water, kept there for at least several hours, small 

 quantities of the water plated out in dilution plates, and the 

 wash water centrifuged in case positive results were obtained. 



2. Tests were made of 21 ants used in certain laboratory 

 and insectary experiments in which they had been permitted 

 to run over chestnut bark bearing spore horns or active peri- 

 thecial pustules of the chestnut blight fungus, Endothia para- 

 sitica. 



3. Five of these 21 ants were found to be carrying spores 

 of the chestnut blight fungus. 



4. Tests were also made of 52 insects and 2 spiders brought 

 in from the field. All but three of these were picked directly 

 from the chestnut blight cankers. 



5. Both of the spiders yielded negative results, while 19 

 of the 52 inst^cts from the field were found to be carrying spores 

 of Endothia parasitica. 



6. Positive results were obtained from insects in the orders 

 Hemiptera, Coleoptera, Diptera, and Hymenoptera. The only 

 other order of insects represented was the Lepidoptera, of 

 which only two individuals were tested, both with negative 

 results. 



7. The number of viable spores of the blight fungus carried 

 varied from 74 to 336,960 per insect. 



8. The cultures from three insects contained no fungous 

 colonies except those of Endothia parasitica. 



9. Each of the eight individuals tested of Leptostylus 

 macula^ one of the beetles which feeds on pustules of the blight 

 fungus, yielded positive results. 



10. The three highest positive results obtained, 336,960, 

 145,340 and 8,538, were from Leptostylus macula. 



11. It was demonstrated that the spores of the blight fungus 

 were easily shaken from the body of this beetle by its own 

 movements. 



12. From the rate of development of the colonies of 

 Endothia parasitica in cultures, it was determined that the 

 insects from the field were carrying pycnospores almost ex- 

 clusively. 



