330 E. H. STRICKLAND. 



EXPLANATION OF PLATE I. 



FIG. i. Prothoracic leg of a Simuliid larva showing the histoblast (a) at an 

 early stage of development. 



FIG. 2, a, band c. Types of spotting on the head of a recently moulted larva 

 of Simiiliiim hirtipes. 



FIG. 3. A single rake from the cephalic fans. 



FIG. 4. Profile of thorax of a half-matured larva showing the histoblasts. 

 a, respiratory organ histoblast (pupal organ); b, wing histoblast (adult organ); 

 c, halterer histoblast (adult organ) ; d, e and /, pro-, meso- and metathoracic leg 

 histoblasts (adult organs). 



FIG. 5. Ventral view of a Simidium larva with Mermis parasites in situ. 



