PLATE lit 



Figure 1. Front view of head of Muscoidean fly, (half in 

 diagram) much enlarged. The heavy black line 

 indicates the ptilinal suture. O = Ocellar plate. 

 FF = Frontalia. PP = Parafrontals. Pfc = Parafacials. 

 CC = Cheeks. EE = Compound eyes. L = Lunula 

 (postfront of larval insects). A = Antennal ridge 

 (mesofront of larval insects). Fp = Mesofacial plates 

 (plus facialia equals prefront of larval insects). Fa 

 Fa = Facialia. (Parts from lunula to facialia both 

 inclusive taken together constitute the front of larval 

 insects). Ep = Epistoma. Cl = Clypeus. PI PI = Palpi. 

 Copied, with the above description, from Townsend. 



Figure 2. The facets of the compound eye of Tabanus. 



Figure 3. The head of Haematopota pluvialis, $ seen from 

 the front, pg., pigment spots. These are of frequent 

 occurrence in the Tabanidae, and are useful in 

 distinguishing species. This is an example of a 

 dichoptic fly. 



Figure 4. Scheme of the mouth parts in the Orthorraphic Diptera. 

 Observe the abductor and adductor muscles of the 

 mandible, ab.m. and ad.m., and the protractor and 

 retractor muscles of the maxilla, p.mx. and r.mx. 



Figure 5. Scheme of the sucking apparatus in the Orthorraphic 

 Diptera. 



