THE CELEKY FLY. 299 



Trhen seen througli a microscope, their plumage glittering as if 

 made of burnished gold and silver. Indeed, one genus in which 

 these leaf-miners are comprised, is named Argyromiges, a title 

 based on a Greek word signifying silver. 



The species which is most common in the leaves of the rose- 

 tree is the Eed-Headed Pigmy (Microseiia ruficapitella). The 

 larva of this insect seems not to possess even the rudiments of 

 legs, and forces itself through the leaf by means of certain pro- 

 jections of the skin, which are sharp and angular, and serve as 

 instruments of progression, like the abdominal scales of the 

 serpent and the bristles of the earthworm. A species which is 

 found in the leaf of the oak is known to collectors by the name 

 of Cramer's Pigmy {Argyromiges Gramerella). The caterpillars of 

 the Dagger Moth (Diurnea), also live between the membranes 

 of leaves, and are remarkable for the last pair of feet, which are 

 shaped like a couple of very minute battledores. These feet are 

 spread out greatly in the act of walking, and the creature is 

 further aided in its progress by the hair-covered warts upon 

 the body. 



As for the beetle leaf-miners, they are to be found among the 

 weevils ; and it is a remarkable fact that one of these insects 

 belongs to the genus Cionus, which has already been mentioned 

 on page 278, as the weaver of certain beautiful pensile cocoons. 



Of the Diptera, the Celery Fly (Tephritis onopordinii) is a 

 good example. The larva of this really pretty fly, with its green 

 eyes and black and white spotted wings^ feeds not only on the 

 celery but on the parsnip, and does great harm to both plants. 

 Gardeners often employ little boys to examine the celery plants, 

 and whenever they find a " blister," as they technically call it, 

 to crush the inclosed maggot between the fingers. The colour 

 of this larva is pale green, so that it is not readily seen even 

 when the blister is opened. If allowed to have its own way, the 

 larva remains in the leaf until it has finished its eating, and 

 then descends into the ground, where it changes into the pupal 

 state, and remains until the following spring. In such a case, 

 the leaves are often much damaged, the blisters being yellowish 

 white, and the leaf itself drooping and half withered. 



Our last examples of peusUe nests are taken from the Arach- 

 nida, being formed by several species of spiders. 



