Insects and Parasitic Diseases. 61 



average dibtaiice of 0.1353 mm. ; the length of the pharynx is from 

 0.046 nun. -0.049 mm., or an average of 0.047 n)m. 



In Table 2 (H. microstoma fi'om "clean " adult Stomoxys calcit- 

 riins), Specimens 1-6, all of which are in the same relative stage of 

 development as the above, show the body to be l.GOO mm. -1.815 

 mm. long, the average being 1.731. The length of the oesophagus, 

 is 0.65 m.m. -0.792 nnn., or an average length of 0.7403 mm. 

 The distance of the nerve-ring from the anterior end of the body is 

 0.105 mm. to 0.132 mm. long, or an average distance of 0.1194 mm. 

 (in five specimens only). The length of the pharynx is 0.046 mm.. 

 0.053 mm., or an average length of 0.0505 mm. 



Table 3 (H. megastoma from '* clean " adult Musca domestica) 

 includes only one specimen in a stage comparable with the above, 

 i.e., the sixth stage. This worm (Specimen No. 1) measured 

 2.805 mm. long. The oesophagus, nerve-ring and base of the 

 pharynx were distant respectively 0.63 mm., 0.138 nnn., and 0.066 

 mm. from the anterior end of the body. 



In Table 4 (H. megastoma from tumours), Specimens 1-6, all of 

 w^hich are in the same stage of development as Specimen 1 in Table 

 3, show the length of the body to be 2.310 mm. -2. 805 mm. long, or 

 an average length of 2.678 mm. Tlie length of the oesophagus is 

 0.58 mm. -0.75 mm., or an average length of 0.685 mm. The dis- 

 tance of the nerve-ring from the anterior end of the body is 0.148 

 mm. -0.181 mm., or an average distance of 0.164 mm. The pharynx 

 varied in length from 0.079 mm. -0.089 mm. the average length 

 being 0.083 mm. 



The following tabulated statement shows the average length of 

 the body and parts referred to of the above six specimens each of 

 H. muscae, H. microstoma (from '* clean " adult flies), and H. 

 megastoma (from tumours) and of one H. megastoma from a 

 *' clean " adult fly. Unfortunately only one H. megastoma from 

 a fly was available for measurement. 



H. muscae H. microstoma H. mejfastoma H. megastoma 



Length of body - 

 Oesophagfus, base fiora 

 anterior end of Vjody 

 Nerve Ring 

 Pharynx - - - 



J= S rt 



■^ ^ ^ 



z rt 



x: c c 



?ll 



^2^' 



S,c-| 



?2g 



^^ii . 



-if . 



^5 S 



'^ii 



*- > O 50 



^ > O r 



r- O O • 









5 -% 



Jll 



mm. 



mm. 



mm. 



mm. 



2.39S 



].731 



2.244 



2.678 



.898 



.740 



.630 



.686- 



.135 



.119 



.138 



.164- 



.047 



.050 



.066 



.085 



