32 



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EXPLANATION OF PLATES. 

 PLATE I. 



Fig. 1. Leptostylus macula Say, one of the beetles which 

 feeds on pustules of the chestnut blight fungus. 



Fig. 2. Piece of chestnut bark showing pustules of the chest- 

 nut blight fungus eaten out by Leptostylus macula. 



PLATE II. 



Fig. 3. Series of cultures 6 days old obtained in the test 

 of insect No. 30, Leptostylus macula. The upper Petri dish 

 contained 1-100 of the water in which the insect was washed; 

 the plate at the lower left contained 1-480 ; and the one at the 

 lower right, 1-960. The last mentioned plate contained only 

 one fungous colony other than Endothia parasitica; the other 

 two represented pure cultures of the chestnut blight fungus. 



