THE FLIES THAT CAUSE MYIASIS IN MAX 59 



5. Mesonotum convex : mesothoracic spiracle with bright orange hair ; 



preacrostica] bristles well developed Phormia Robineau-Desvoids 



Mesonotum flattened on the disc; mesothoracic spiracle with dark 

 hair : preacrostical bristles absent or vestigial Protophormia Townsend 



6. Propleuia bare; nonmetallic species 7 



Propleura pil« »se 10 



7. Prosternum pilose ; haustellnm somewhat swollen ; yellowish species, 



with only ordinary pile 8 



Prosternum bare: haustellnm not at all swollen; blackish species. 

 with abundant crinkly yellowish hairs on the sides and dorsum of 

 the thorax Pollenia Robineau-Desvoidy 



8. Vein r, ciliated almost to cross vein r-m : a small but distinct costal spine 



present; eyes of both sexes broadly separated, the frontalia in the male 

 not narrowed posteriorly: second abdominal segment especially long 



(tig. 36) Auchmeromyia Brauer and Bergenstamm 



Vein /- ciliated less than halfway to cross vein r-m; costal spine 

 absent; eyes of the male but narrowly separated, the frontalia almost 

 obliterated behind : second abdominal segment of ordinary length 9 



9. Front of male narrow, the eyes almost contiguous ; proclinate fronto- 



orhitals present in the female Cordylobia Griinberg 



Front of male about one-fourth the head width; proclinate fronto-orbi- 

 tals absent in the female Stasisia Surcouf 



10. Lower squama bare above 11 



Lower squama pilose above 12 



11. Subcostal selerite with only soft pubescence Phoenicia Robineau-Desvoidy 



Subcostal selerite pilose Lucilia Robineau-Desvoidy 



12. Abdomen entirely metallic blue, green, or violet 13 



Abdomen wholly nonmetallic. or at least broadly yellow on the base, Bides, 



and venter Calliphora Robineau-Desvoidy (broad sense, in part) 



13. Scutellum with three strong lateral bristles Cynomyopsis Townsend 



Scutellum with at least four strong lateral bristles Calliphora Robineau- 

 Desvoidy (in part) 



Lakvae (Nearctic Region, Second Stage) 4 



1. Oral hooks tapering to a point 2 



Oral hooks enlarged near the tips, then tapering beyond the enlarge- 

 ment Lucilia. Phoenicia, Calliphora, Cynomyopsis 



2. Tracheal trunks leading from the posterior spiracles pigmented, dark 



brown to black (fig 21, A) Callitroga americana (Cushing and Patton) 



Tracheal trunks leading from the posterior spiracles not pigmented 3 



3. Dorsal spines present on posterior margin of segment 11 4 



Dorsal spines absent on posterior margin of segment 11 5 



4. Dorsal spines absent on posterior margin of segment 10. 



Phormia regina (Meigen) 

 Dorsal spines present on posterior margin of segment 10. 



Protophormia terrac-norac (Robineau-Desvoidy) 



5. Ratio of distance between inner tubercles on upper margin of posterior 



cavity and distance between inner and median tubercles on each side 



approximately 1.5 to 1 CaUitroga maceUaria ( Fabricius) 



Ratio of distance between tubercles mentioned above approximately 

 1.1 to 1 Paralucilia wheeleri I Hough) 



Larvae (Xearctic Region, Third Stage) 5 



1. Peritreme of posterior spiracle incomplete and not enclosing the button, 



the latter sometimes poorly defined (figs. 32. B and 35. E) 2 



Peritreme of posterior spiracle complete, though sometimes weakened 

 in the area of the button (fig. 41, B) 6 



4 Modified from Knipling (7 4) and Hall (Jrf). 



5 Modified from Hall (49) and Knipling (74). 



