THE STUDY OF DIPTERA 



87 



mass of facts which have accumulated resfardincc the classifica- 

 tion, structure, and habits of our native species, which, by the 

 way, number considerably over three thousand. Taking the 

 subject from a merely systematic point of view, it may be 

 remarked that the identification of the constituents of quite 

 a small collection, such as, for instance, might be obtained in 

 the field on a single sunny morning, necessitates reference 

 to quite a number of books and scattered papers written in 

 English, French, German, Latin, Dutch, and perhaps other 

 languages. It is true, a few volumes have been published in 

 recent years dealing with certain families (mainly from the 

 systematic point of view), but I know of no general up-to- 

 date work giving a summary of our knowledge of all groups 

 from a biological as well as a taxonomic aspect. And }-et a 

 knowledge of our native species would serve as an admirable 

 introduction to the study of those of the world in general, 

 for out of a total of seventy-four existing families no fewer 

 than sixty-four are represented in our own fauna. 



Apart from the importance of Flies from an economic 

 point of view, they are highly worthy of study on account 

 of their great and interesting diversity in form and habit. 

 Were they a little better known, it is certain that they would 

 attract a host of students ; no insects are more easily 

 collected and preserved, and no group more amply repays 

 the collector. The chance of making some interesting dis- 

 covery and the likelihood of capturing species not hitherto 

 obtained in this country are both greater than in the case of 

 well-studied groups such as Butterflies, Moths, or Beetles. 

 Every family of Flies has a particular interest of its own, and 

 the majority still require careful investigation in many 

 ways. Much still remains to be done by the systematist in 

 differentiating the species, while those interested in their 

 external structure will find ample scope for useful work in 

 regard to the mouth-parts, genitalia, or that comparatively 

 new subject known as chaetotaxy, which concerns the arrange- 

 ment of the bristles on the various parts of the body. For 

 those willing to work out life-histories there is an enormous 

 field for research, for only the fringe of this subject has been 

 touched ; while finall\-, regarding the more difficult domains 



