106 Insects most injurious to Cultivators. 



The general colour of the body varies from rusty brown to 

 shining black ; the head buff, with black hairs ; the legs and 

 halteres yellow ; the thorax with long black lateral hairs ; the 

 wings black, with numerous limpid spots of various forms and 

 sizes ; the scutellum often paler rusty coloured. In some spe- 

 cimens dark markings of the wings are varied with paler fulvous, 

 presenting a still more beautiful appearance. The under side 

 of the body is paler yellow. The abdomen and thorax are 

 highly polished. It is about one sixth of an inch long, the ex- 

 pansion of the wings being about one third of an inch. 



The motions of this fly are very peculiar, seated upon a leaf 

 in the sunshine, their wings are carried partially extended, and 

 at the same time partially elevated ; and they have a sideling 

 kind of motion, which they possess in common with but few 

 other Diptera. I have generally found them in the perfect state 

 basking on the broad leaves of the laurel. Fabricius and Mac- 

 quart say they frequent the thistle. Fallen is silent as to their 

 habits. From the specific names which have been given to 

 them, it might be supposed that they were attached to the 

 Onopordum and Centaurea; but such I do not apprehend to 

 be the case, as we generally find that, if a species attached to a 

 particular plant is compelled to resort to another plant for food, 

 it is generally of the same natural order as its real food. I have 

 found these flies throughout the summer, and, from what I have 

 observed above, as to the discovery of different-sized larva? on 

 the same leaf, I have no doubt that, like the house-fly, there is 

 a succession of generations throughout the year. I have, for 

 instance, found seedling celery in pots attacked at the beginning 

 of summer, and I presume that these individuals arrive, in a 

 comparatively short time, at the perfect state, and that their 

 progeny continue to increase without any regularity in the 

 period of the broods. The extermination of the insect must be 

 looked to from the earliest appearance of the withering of the 

 leaves. To destroy the perfect fly seems impracticable ; al- 

 though, perhaps, hanging lines of string covered with bird- 

 lime, over the rows of celery, might be attended with success. 

 The plucking off of the infested leaves, or the crushing of the 

 larva with the hand, without destroying the leaf, is recommended 

 by Major, and appears very likely to be successful, if adopted 

 in the beginning of the summer, as the destruction of one grub at 

 that period will not only prevent the production of a numerous 

 progeny, but will also insure the better growth of the yet ten- 

 der plant. 



The other species of leaf-miner, proposed to be noticed in 

 this article, attacks the chysanthemum, and has been communi- 

 cated to me by my friend Mr. Ingpen, the description of 

 whose admirably kept garden has formed the subject of one of 



