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



2. Posterior margin of segment 11 without dorsal spines ; posterior spiracle 



without a definite button 3 



Posterior margin of segment 11 with dorsal spines ; posterior spiracle 

 with a definite button 5 



3. Tracheal trunks leading from posterior spiracle not pigmented 



(fig. 21, B) 4 



Tracheal trunks leading from posterior spiracles pigmented, dark brown 

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



4. Accessory oral sclerite absent (fig. 22) Callitroga ma cellaria (Fabricius) 



Accessory oral sclerite present (fig. 6, B) Paralucilia wheeleri (Hough) 



5. Dorsal spines present on posterior margin of segment 10 ; larger tubercles 



on upper margin of posterior cavity distinctly longer than half the 

 width of one posterior spiracle. 



Protophormia terrae-novae (Robineau-Desvoidy) 

 Dorsal spines absent on posterior margin of segment 10; length of 

 above-mentioned tubercles less than half the width of one posterior 

 spiracle Phormia regina (Meigen) 



6. Peritreme of posterior spiracles weakly sclerotized. 



Pollenia rudis (Fabricius) 

 Peritreme of posterior spiracles strongly sclerotized 7 



7. Accessory oral sclerite absent 8 



Accessory oral sclerite present (fig. 6, B) 10 



8. Pharynx without a pigmented area below the posterior extremity of 



the ventral horn Lucilia illustris (Meigen) 



Pharynx with a prominent pigmented area below the posterior extremity 



of the ventral horn 9 



_9. Inner tubercles on the upper margin of the posterior cavity separated 



by a distance approximately equal to the distance between the inner 



and outer tubercles Phaenicia pallescens (Shannon) 



Inner tubercles on the upper margin of the posterior cavity separated 



by a distance approximately equal to the distance between the inner 



and median tubercles Phaenicia sericata (Meigen) 



10. Labial sclerite with toothlike apical portion longer than the greatest 



width of the basal portion Calliphora vicina Robineau-Desvoidy 



Labial sclerite with the toothlike apical portion as long as the greatest 



width of the basal portion__ Cynomyopsis cadaver ina (Robineau-Desvoidy) 



larvae (Ethiopian Region, Third Stage) 



1. Grublike species 2 



Maggotlike species 4 



2. Cuticle devoid of obvious spines and with numerous longitudinal and 



horizontal sulci (fig. 37, A) ; anterior spiracles not projecting but 

 flush with the surface; posterior spiracles very widely separated, 

 with 3 straight, short, outwardly directed slits (fig. 37, B). 



Auchmeromyia Brauer and Bergenstamm 

 Cuticle armed with obvious spines ; anterior spiracles consisting of 

 membranous stalks bearing a number of small fingerlike processes ; 

 posterior spiracles not widely separated, the breathing slits serpentine 

 or sinuous 3 



3. Spines of cuticle small and often grouped in transverse rows of 3 or more 



(fig. 39, A) ; no bar of spiny processes between the oral hooks; toothed 

 plate bearing about 6 small yellow teeth (fig. 40, A) ; posterior spiracle 



small with 3 short sinuous slits (fig. 40, B) Cordylobia Griinberg 



Spines large and not grouped in transverse rows (fig. 39, B) ; a dark 

 bar of spiny processes present between the oral hooks ; toothed plate 

 bearing about 10 yellow-brown teeth arranged in 2 rows (fig. 40, G) ', 

 posterior spiracle rather large, with 3 long serpentine slits, of which 

 at least 1 may show fragmentation into 2 parts (fig. 40, D) . 



Stasisia Surcouf 



4. Peritreme of posterior spiracles incomplete, the button outside the sclero- 



tized area (figs. 33. B and 35, E) Chrysomya Robineau-Desvoidy 



Peritreme of posterior spiracles complete and enclosing the button 

 (fig. 41, B) 5 



5. Accessory oral sclerite absent Phaenicia Robineau-Desvoidy 



Accessory oral sclerite present (fig. 6, B) Calliphora Robineau-Desvoidy 



