284 The Scottish Naturalist. 



related to the Muscidae ; under which they are sometimes ranked' 

 and which they resemble greatly in form ; though they are usually 

 of rather smaller average size. Many of the species have brilliant 

 golden-green eyes, and dark spots or bands on the wings ; and the 

 females have a more or less prominent ovipositor, to serve for de- 

 positing their eggs in a suitable place in the tissues of the plants 

 on which the larvae feed. Some of the latter mine in the 

 leaves, forming large pale blotches, e.g., Tephritis Onopordinis in 

 the parsnip and celery. Others live in fruits of various plants, 

 e.g, in rosehips, barberries, &c. A large number are almost, if 

 not altogether, restricted to the natural order Compositae ; most 

 of these feed in the receptacles, at the base of the head of flowers, 

 and often they do great damage to the ovaries and seeds. A 

 good many of the insects in this family are very common in the 

 larval condition, though the flies are not often seen unless specially 

 looked for or reared. But besides those that live in the almost 

 unaltered parts of plants there are several gall-makers among the 

 TrypetidcB ; and though I have been unable to identify more 

 than one species from Scotland, I have found galls that would in- 

 dicate others also as existing here. The Scotch galls referable 

 to this group are all modified ovaries of Compositae ; I have 

 specimens from Centaurea nigra (the work of Trypeta solstitialis), 

 llypochaeris radicata, and Hieracium corymbosum. In all of these 

 the ovaries have become hard and woody, and a good deal 

 enlarged ; and there is a small opening at the upper end of each. 

 In some parts of England the stems of thistles (Carduus lanceolatus, 

 &c), frequently bear a woody swelling an inch or more in length, 

 and nearly an inch in breadth, the work of another fly of this 

 group named Urophora Cardui L. 



III. We now come to the gall-making Diptera par excellence ; 

 I refer to the Cecidomyidae or Gall-midges. These insects 

 form a very large proportion of the galls of, at least, European 

 countries ; and they are known to occur in most parts of the 

 world. Probably no group of gall-makers equals them in number 

 (except perhaps the mite-galls, if we include every kind of de- 

 formity caused by the genus Phytoptus). From many galls the 

 makers have not yet been reared ; but it is so easy to recognise 

 with certainty the group to which the larvae belong that there need 

 be no doubt in referring a gall to the group of Cecidomyidae if the 

 larvae are in it, and show the well-known features of that group. 



