184: mSECTS INJURIOUS TO THE PEAB. 



fourth, the Imago, which is the perfect or winged state. In this last 

 stage only are the differences of sex discernible ; and by the Fly, or 

 perfect insect, the eggs are deposited which reproduce the brood of 

 destructive worms, 



" This fly of the Pear Slug is described as a four-winged Hymenopter- 

 ous (or wasp-like) insect, of a glossy black color. The wings are some- 

 what convex on the upper side, and slightly wrinkled, transparent, 

 reflecting the colors of the rainbow, the anterior pair having a smoky 

 band across them. The legs are tipped with a dull yellow color. The 

 body of the female measures rather more than a fifth of an inch 

 in length, that of the male is smaller. They make their appearance 

 twice during the summer, the first time about the end of May or the 

 first of June, the second appearance about the latter end of July. On 

 each occasion they lay their eggs, and disappear in about three weeks. 



Fig. 60. 



Fig. 60. The Perfect Insect or Fly of the Pear Slag— magnified. The cross lines 

 represent the natural size. 



" The slug fly deposits its eggs singly on the upper surface of the most 

 matured leaves, covering it with a frothy, white, varnish-like mucilage, 

 which surrounds it, and serves at once to attach it to the leaf, and to 

 exclude the atmosphere. The small spot a on the leaf. Fig. 59, repre- 

 sents the size and form of the egg, which is seen as a dark center in the 

 middle of a white spot. Fig. 61 represents the egg magniaed, and the 

 worm or young slug within the semi-transparent shell. Fig. 62 exhibits 

 the egg also magnified, after the insect has emerged. 



"When first hatched, the young slug is white, andean with diflficulty 

 be discerned by the naked eye ; it commences immediately to puncture 

 with small holes the surface of the leaf upon which it is produced. It 



