400 



VII. 



THYSANOPTERA. 



The very small black flies which are such a source of annoyance ti 

 travellers in the summer-time, and which fly into our eyes and craw 

 over our faces during the prevalence of warm windy weather, princ 

 pally belong to a kind of insect which is characterised by having ver 

 remarkable wings when in the adult condition. These insects exh 

 by myriads, and there are several species of them ; and they are a 

 exceedingly destructive to flowers, and especially to the bloom ( 

 cereal plants. The little black insects are to be seen on almor 

 every flower, and they devour the delicate cellular tissues of th 



Figs. 381, 382.— The Adult Insect and Larva of Tkrips c.etealiiu}i (magnified). 



petals. Thrips cerealium is very destructive when it occurs in mu 

 tudes upon the wheat, barley, and oats, for it interferes with t 

 proper nutrition of the grain, by nibbling the protecting enveloj: 

 and the tissue which connects it to the stalk. 



All the members of the genus Thrips — and they alone constiti 

 the order now under consideration — possess four very narrow me 

 branous wings, without any folds or network upon them, but furnish 

 and decorated with beautiful fringes upon the edges. These frim > 



