120 MISC. PUBLICATION 631, U. S. DEPT. OF AGRICULTURE 



6. Second anal vein very short ; the third curved forward in such a way that 



if the two were produced, they would intersect ( fig. 71 ) 



Fanhia Robineau-Desvoidy 

 Second anal vein of moderate length, the third not as above described 7 



7. Grayish or black species, often shining ; front femur of male deformed near 



the apex (lig. 64) Hydrofaea Robineau-Desvoidy 



Figure 64. — Hydrotaea meteorica, inner side view of right front femur of male. 



Black species, with a metallic-blue abdomen ; front femur of male not de- 

 formed near the apex Peronia Robineau-Desvoidy 



8. Arista haired above only ; proboscis long, slender, shining, and rigid, with 



small labella (fig. 74) Stomoxys Geoffroy 



Arista haired above and below ; proboscis shorter and thicker, with large 

 labella (fig. 81) 9 



9. Vein Wi +2 broadly rounded at its bend (fig. 78) ; longest aristal hairs not 



half so long as the last aristal segment Muscina Robineau-Desvoidy 



Vein mi+a angularly rounded at its bend (fig. 82) ; longest aristal hairs 

 almost as long as the last aristal segment Musca Linnaeus 



FIRST-STAGE LARVAE (AFTER TAO) 



1. Larvae of the normal muscoid shape, without lateral processes 2 



Larvae with prominent lateral processes Fannia Robineau-Desvoidy 



2. Posterior end round and smooth Musca Linnaeus 



Posterior end with papillae 3 



3. Lateral plate of pharyngeal sclerites broader dorsoventrally than 



anteroposteriorly Muscina Robineau-Desvoidy 



Lateral plate of pharyngeal sclerites broader anteroposteriorly than 

 dorsoventrally Stomoxys Geoffroy 



SECOND-STAGE LARVAE (PARTLY AFTER TAO) 



1. Larvae of the normal muscoid shape, without lateral processes 2 



Larvae with prominent lateral processes Fannia Robineau-Desvoidy 



2. Posterior end round and smooth Musca Linnaeus 



Posterior end with papillae 3 



3. Lateral plates of pharyngeal sclerites very broad ; the ventral horn twice 



as long as dorsal horn Stomoxys Geoffroy 



Lateral plates of pharyngeal sclerites narrow ; ventral horn slightly 

 shorter than dorsal horn Muscina Robineau-Desvoidy 



THIRD-STAGE LARVAE 



1. Larvae of the normal muscoid shape, without lateral processes (fig. 



83) 2 



Larvae flattened, with prominent lateral processes (figs. 70 and 

 72) Fannia Robineau-Desvoidy 



2. Slits of posterior spiracles strongly sinuous 3 



Slits of posterior spiracles straight or arcuate 5 



3. Slits of posterior spiracles each with 2 loops, S-shaped ; posterior end with 



setulose tubercles ventrally 4 



Slits of posterior spiracles each with 3 loops or more (fig. 80) ; posterior 

 end smoothly rounded Musca Linnaeus 



4. Posterior face of larvae much higher than broad ; the setulose tubercles 



very prominent (fig. 67) slits of posterior spiracle not surrounding 



the button (fig. 68) Synthesiomyia Brauer and Bergenstamm 



Posterior face of larvae not much higher than broad; the setulose 

 tubercles only moderately prominent; slits of posterior spiracles sur- 

 rounding the button (fig. 75) Stomoxys Geoffroy 



5. Posterior spiracles oval, diverging above ; their lower slit directed sharply 



away from the upper two (fig. 65) Anthomyia Meigen 



Posterior spiracles rounded, with their slits not as above described 6 



