PREFACE 



npHE world-wide interest which has been created during the 

 last few years in the relation which the house-fly bears to the 

 hygienic state of the individual and of the community, as a 

 product of insanitary conditions and as a potential and not in- 

 frequent disseminator of certain common and preventable infec- 

 tious diseases, has rendered the presentation of our knowledge of 

 this insect, its habits and relation to disease most desirable and, 

 indeed, necessary as a means of appreciating its significance from 

 the entomological and medical standpoint and as a basis for 

 further investigation. 



In 1907, 1908 and 1909 respectively the three parts of my 

 monograph on the House-fly were published in the Quarterly 

 Journal of Microscopical Science under the title : " The Structure, 

 Development and Bionomics of the House-fly, Musca domestica 

 Linn." For the convenience of workers the Manchester University 

 Press very kindly republished in volume form two hundred copies 

 of the letterpress and plates of the monograph, which reprints 

 Sir Ray Lankester, the Editor of the Q. J. M. S., permitted me 

 to obtain. With a certain amount of additional matter in the 

 form of appendices this limited edition was issued in 1910 under 

 the title : "The House-fly, Musca domestica Linn. A Study of the 

 Structure, Development, Bionomics and Economy." This reprint 

 is now exhausted. 



Although the present volume contains the whole of the 

 original matter published in the Quarterly Journal of Mic7^o- 

 scopical Science, the extent of subsequent work by investigators 



