VIU INDEX TO PLATES. 



Fig. 3. One of the halteres. 



Fig. 8 a, h. Vesicles at the base of the same, highly 



magnified. 

 Fig. 4. Leg of Fly : a, coxa ; h, trochanter ; c, femur ; 



e, tibia ; f, tarsus. 

 Fig. 5. Trachea, or respiratory tube, with coil. 



Pl. Vn page 54 



Fig. 1. Last joint of tarsus, or foot of Fly, with hooks 



and pads. 

 Fig. 1 a. Portion of fringe, magnified 900 diameters, to 



show the supposed suckers. 

 Fig. 3. One of the stigmata or breathing-apertures, 



shown by transmitted light. 



Pl. Vm. (Figures after Griffith.) 64 



Fig. 1. Larva of House-fly (natural size). 



Fig. 1 a. The same (magnified). 



Fig. 2. Pupa (natural size). 



Fig. 3. Lid of pupa-case (magnified). 



Fig. 4. Anterior extremity of larva, showing hooks 

 (magnified). 



Fig. 5. Anterior extremity of larva, with palps retracted. 



Fig. 6. Anterior extremity of larva, with the same ex- 

 panded, showing also the trachea and rudi- 

 mentary feet. 



