— 132 — 



says ' ' If you traverse a field of wheat or rye a week or a fort- 

 night before harvest you may observe a greater or less considera- 

 ble number of the stems the straight and whitened ears of which 

 elevate themselves above the others, and appear to have attained 

 their perfect maturity. They form a striking contrast with the 

 neighboring plants which are still very green ; and the heavy ears 

 filled with grains are inflexed and bent towards the earth whilst 

 the others are entirely empty, or contain only a very small num- 

 ber of grains, which are for the most part shrunk and homy." 

 The same writer in referring to the circular cut made by the larva 

 before spinning its cocoon states that: "In consequence of this 

 section, the straw, having no more sustenance, breaks off at the 

 foot and falls to the ground when the wind becomes a little strong ; 

 the field then presents the same appearance as if it had been 

 traversed in every direction by sportsmen or by animals." 



In this country, according to my observations, the injury to the 

 wheat by this insect produces results .somewhat different from 

 tho.se just described. I found the same lodging of the wheat 

 caused by the circular cut near the root ; but this lodging of the 

 grain appears to be the chief injury here. 



I did not find that the presence of a larva in a stalk cati.sed the 

 complete destruction of the seed described by European writers. 

 In fact, in most cases, the grain shelled from a certain number of 

 infested heads weighed more than the grain shelled from the same 

 number of non-infested heads taken from the same bundle in regu- 

 lar order after the infested ones had been removed.* 



This was at first very puzzling. It seemed to point to the ab- 

 surd conclusion that the presence of this lx>rer within a .stalk in- 

 crea.sed the amount of grain produced by that stalk. It was 

 noted, however, that the infested stalks were almost invariably 

 large, healthy ones, with good well filled heads. When we re- 

 call the fact that the laying of the eggs takes place while the 

 wheat is still small, and that a .stalk must be large enough to con- 

 tain a hollow of considerable size before it is suitable for the de- 

 velopment of a larva, it will be .seen that the stalks infested will 

 naturally be tho.se that are the largest early in the season ; while 

 the stalks that are backward in their development, and conse- 

 quently will produce smaller heads, will escape the attack of the 

 insect. Therefore, a compari.son of heads from infested stalks 



* See note 7. 



