A EEOOED OF SOME EXPEEIMENTS EELATIXG TO THE 

 EFFECT OF THE PUNCTUEE OF SOME HEMIPTEEOUS IN- 

 SECTS UPON SHEtTBS, FETJITS, AND GEAINS, 1886. 



By F. M. Webster, Special Agent. 



LETTER OF TRANSMITTAL. 



La Fayette, Ixd., October 15, 1886. 

 Sir : I herewith give results of my experiments with Hemiptera, principally Lygus 

 pratensis L. 



F. M. WEBSTER. 

 Prof. C. V. Riley, 



U.S. Entomologist. 



The object of the following experiments was to determine the effect 

 of the punctures, or the withdrawing of sap from shrubs, the juices 

 from berries, and the milk from ripening grain ; and if possible to settle 

 the point as to whether or not these Hemiptera, in thus partaking of 

 their food, eject a poisonous saliva into the wounds which they neces- 

 sarily produce, and thereby cause the death of the punctured object. 



All insects were confined upon these shrubs, fruits, and grains by 

 means of a sack of Swiss muslin, drawn over the object and tied, the 

 stem being protected from undue pressure by cotton placed in the 

 mouth of the sack. 



Experiment 1. 



Pcecilocapsus quadrivittatus. 



May 22, a number of adults were confined upon two or three inches 

 of terminal portions of a young pear shoot. 



Result. — Within one week the shoot withered, and afterwards the 

 leaves and bads died, and turned black as far down as the muslin sack 

 extended, but below that point no effect was noticeable. Later, after 

 the insects had also perished, new leaves were put forth within the sack. 



Experiment 2. 



Lygus pratensis L. 



May 20, placed adults on shoots of Concord grape. 

 Result. — May 28, no effect could be noticed. 



54 



