148 THE CLOUDED TORTRIX MOTH. 



One of the oddest things connected with this 

 Moth is the fact that its numbers are greatly 

 decreased "by means of a little fly belonging to 

 the genus Empis. This fly possesses a long 

 and sharp proboscis, by means of which it can 

 .suck the life-juices out of the Moth. Unlike 

 most insects of prey, it does not only catch its 

 prey while on the wing, but retains it in the 



Groen Oak Moth. Oak Moth and Empis Fly. 



clasp of its long and slender legs while the 

 proboscis is draining the poor little Moth of its 

 blood. I have captured great numbers of the 

 Empis while thus engaged, and the above illus- 

 tration represents the fly as it appears while 

 destroying the Moth. 



Still keeping to this genus, we have the 

 CLOUDED TORTRIX (Tortrix semialbana), a figure of 

 which is given on Plate XI. fig. 4. The ground 

 colour of the upper wings is pale ochreous 

 yellow, and the dark markings, the form of which 

 can be seen by reference to the plate, are brown, 

 slightly differing in depth in various specimens. 



