82 



GNATS OR MOSQUITOES — CHAPTER VI 



find that the upper hp is developed into a strong spine ; and 

 that, hidden between it and the lower lip are four short, 

 stout blades, each of which has exactly the form of a Roman 

 sword. These blades are the mandibles and maxillae, and 

 are capable of inflicting a sharp bite or rather puncture, but 

 the lower lip remains practically identical with that of the 

 blow fly. 



Fig 17. — Mouth parts of an Indian Sand fly (Phlebotomus), the Labuum 

 HAVING bp:en removed and placed separately to the left. 



a, labrum; b, mandible; c, labium; k, " hypopharynx " ; w, maxilla; 

 X, maxillary palp, that of the left side being shown bent ; as habitually held 

 during life when at rest. 



If we now examine the further modified mouth of a 

 sand fly, we find that the lower lip, though obviously 

 approaching in form to that of the Mosquito, is still recog- 

 nisably the same organ as the " tongue " of flies. The four 

 miniature, sword-like blades of the mandibles and maxiilaj 

 are present, and almost identical in shape with those of the 

 horse fly. There is, however, now an additional median 

 organ lying in the midst of this bundle of weapons, in the 

 shape of a conical tube, sharp at the point and very broad 

 at the base, prolonged from the mouth cavity. This organ 

 is the hypopharynx, and with this addition, we have now 



