PLATE I. 



Diagram of the Exterior Parts of a Fly, a full description of 

 which will be found on pages 8-21, to which should be added 

 under Abdomen, page 20 : The abdomen is said to be depressed 

 when it is pressed together above and below till almost flat — 

 the section would be like o ; compressed when pressed together 

 at the sides — the section would be like 0; an d cylindrical when 

 not pressed together from any direction — the section would be 

 like O. 



Note. 



It will be understood that all the parts shown opposite are not to be 

 found on any single species ; and the drawings on the six plates which 

 follow are not to be considered as full or correct in every detail, but as 

 illustrating the particular characters in the tables to which the plate- 

 reference is made. They are given to try to make the meaning of terms 

 or characters a little clearer. The sizes are not at all proportionate. 



