OF HARTING. 3/3 



we have captured four or five specimens, and seen 

 probably as many others which are equally entitled 

 to the distinction of being included in our list. It may 

 be objected that, probably all these were imported 

 as larvae or pupae in the Norway deals that were occa- 

 sionally stacked in the yard with timber of native 

 growth ; but although the greater number of our 

 captures of this fine insect were made in the timber- 

 yard, a few were taken in Padswood Copse on the 

 trunks of living Scotch firs. It is a fine large black- 

 and-yellow fly, at the first glance suggesting some 

 resemblance to a hornet, but of a more cylindrical 

 form, about an inch long, with a borer from three- 

 eights to half-an-inch more, and makes a loud buzzing 

 noise during flight. 



The Gall flies, forming the third family, have given 

 rise, from a very early period in the annals of natural 

 history, to some ingenious theories. The female 

 insects, in the act of oviposition, introduce into the 

 punctures they make in the leaves, stems, roots, and 

 other parts of various plants for the reception of their 

 eggs, an irritating fluid, which has the property of 

 producing in a very short time those curious ex- 

 crescences popularly known as galls.* The question 

 on which speculation has been rife, and which still 

 awaits solution at the hands of vegetable physiologists, 

 is how these abnormal growths are effected, and what 

 explanation can be given of the fact, that among the 

 many distinct forms they assume, although all the 

 result of the same simple process of oviposition, each 

 one is peculiar to a single species of fly only. For 

 instance, the little globular berry-like galls on the 

 leaves of the oak are those of Cynips quercus folii; 



Another and more recent theory, which dispenses with the 

 irritating fluid, is that the egg of the Cynips, being deposited in 

 the cambium layer of a young shoot, acts as a spherical nucleus 

 round which the sap courses, and thus causes the development 

 of the gall. 



