THE FLIES THAT CAUSE MYIASIS IN MAN 61 



Larvae (Australian Region, Third Stage) 6 



1. Peritreme closed; the button situated in the peritreme (fig. 41, B) 2 



Peritreme open; the button indistinct, in the gap of the peritreme (fig. 



32. B) 6 



2. Spiracles very large (more than 0.4 mm. across, separated from each 



other by less than the spiracular length ; peritreme scalloped and 



wide)—' Neopollenia stygia (Fabricius) 



Spiracles much smaller (less than 0.3 mm. across) 3 



3. Spiracles separated by more than the spiracular length: peritreme uol 



scalloped, narrow Neopollenia fallax (Hardy) 



Spiracles separated by not more than the spiracular length 4 



4. Peritreme scalloped and fairly wide, with the part around the button 



projecting prominently: slits far apart; the bottom slit forming an 



angle of 13° to 15° with the horizontal plane Anastellorhina augur 



(Fabricius) 

 Peritreme not scalloped, narrow: spiracular plates separated by less 

 than the spiracular length ; the bottom slit forming an angle of 32° to 

 35° with the horizontal plane 5 



5. Spiracles pear-shaped (that is, longer than broad) ; peritreme thin and 



narrow: slits long and thin (fig. 41. B) Phoenicia sericata (Meigen) 



Spiracles rounded, smaller; peritreme thicker and wider; slits shorter 

 and wider Phoenicia cuprina (Wiedemann) 



6. Larvae hairy, that is, with a transverse row of fleshy tubercles discally 



on each segment (fig. 32, A) 7 



Larvae smooth, without such tubercles Chrysomya micropogon (Bigot) 



7. Larvae large (up to 16 mm.), very hairy, grayish: peritreme forked at 



the opening, which is narrow (cf. G. albiceps, fig. 32, B) Chrysomya 



rufifacies I Macquart) 

 Larvae smaller (up to 11 mm.), much less hairy, brownish; peritreme 

 opening wide Microcalliplwra varipes (Macquart) 



The Genus CALLITROGA Brauer 



(Figs. 21 and 22) 



This genus includes the American screwworm flies. In the litera- 

 ture the species have commonly been referred to CochJiomyia. 



Members of this genus are metallic dull green to bright green or 

 greenish-blue flies of medium size; the head, including the palpi and 

 usually the antennae, is largel} T orange to yellow ; the wings are hyaline. 

 The presence of three prominent longitudinal black stripes on the 

 mesonotum and the short filiform palpi will separate it from related 

 genera. 



As far as is known, the genus is strictly American. There are four 

 species, two of which are known to cause myiasis. The following key, 

 adapted from Hall (^9), will separate the adults: 



KEY TO SPECIES 



1. Parafrontalia with light hair anteriorly outside the frontal row of bristles; 



female with 1 or 2 pairs of proclinate fronto-orbital bristles 2 



Parafrontalia with dark hair anteriorly outside the frontal row of bristL s ; 

 female rarely with fronto-orbital bristles (fig. 23) 



americana (Cashing and Patton) 



2. Fourth abdominal segment strongly pollinose laterally; male without 



fronto-orbital or outer vertical bristles 3 



Fourth abdominal segment nearly shining and with only a trace of pollen 

 laterally; male with reclinate fronto-orbital bristles opposite middle of 

 ocellar triangle and with strong outer verticals minima (Shannon) 



6 After Fuller ( ' f l, P- 78). 





