DURHAM DIPTERA. 1 3 



(B.III.) breathing-hole, which is usually very con- 

 spicuous. A large bristle just above the fore 

 coxa is the prothoracic bristle. 



(2) The Meso-pleura, bounded in front by the pro- 



thoracic suture, above by the dorso-pleural 

 suture, behind by the meso-pleural suture (which 

 comes down from the fore-edge of the wing-base, 

 and is often fringed with bristles), and beneath by 

 the stemo-pleural suture. Near its upper front 

 corner is the stigma, a prominent orifice of the 

 respiratory tubes. A large bristle just below this 

 stigma is the stigmatical bristle. 



(3) The Ptero-pleura below the wings, and behind the 



meso-pleural suture. 



(4) The Meta-pleura, behind the ptero-pleura. "A 



more or less tubercular piece, between the root of 

 the wing and the haltere." 



(5) The Sterno-pleura, a more or less triangular piece, 



above the middle leg, and below the sterno- 

 pleural suture. 



(6) The Hypo-pleura, behind the sterno-pleura, and 



above the hind leg. 



Bristles. — They are named after the region 



on which they are placed, as prothoracic bristle, 



meso-pleural bristle, &c. 



IV. The Meta-Notum. — The part of the thorax behind 



and beneath the scutellum, and between it and the 



back of the abdomen. 



C. APPENDAGES OF THE THORAX. 



I. The Legs, distinguished as fore, mid, and hind, or 

 1 st, 2nd, 3rd. I beg to enter my protest against the 

 unnecessary confusion introduced by the use of the 

 words anterior for the fore and mid legs together, 

 and posterior for the mid and hind legs together. 

 From the use of the words in other connections one 

 is naturally apt to think of them as referring to the 

 fore or hind legs only, and it is just as easy to use 



