116 



INSECTS INJURIOUS TO STAPLE CHOPS. 



fungous diseases — mostly of the genus Empusa — are one 

 of the most important checks to the multiplication of 

 plant-lice, and, as they require wet weather for their best 



Fig. 66. — Wbeat-louse Parasite (Aphidius gr<i.n(iri(iphis Cook), and 

 parasitized louse from which it has issued. (Copied from 

 J. B. Smith.) 



Fig. 67. — The l^he^it-Xoum (Nectar ophor a amnm Fab.). Wingless 

 and winged forms. (After Garman.) 



development, it is not surprising that several dry seasons 

 should precede an abundance of lice. Prof. F. M. Webster 



