THE FLIES THAT CAUSE MYIASIS IX MAX 33 



Head poorly developed, appearing externally as an unsclerotized cephalic 

 segment; antennae usually absent, when present poorly developed and 

 situated on an unsclerotized surface; free cephalopharyngeal skeleton 

 present; mandibles replaced functionally by mouth hooks 6 



2. Head complete, not retractible into the prothorax and separated from it 



by deep incisions (figs. 85 and 87) ; mandibles opposed, moving hori- 

 zontally 3 



Head incomplete, that is. retractile into the prothorax (fig. 89) 4 



3. Each thoracic and abdominal segment divided into 2 or 3 annul i, at least 



some of which bear transverse sclerotized bands dorsally ; the apical 



segment modified into a sclerotized air tube (fig. 85) psychodidae 



The thoracic and abdominal segments not divided into annuli. but each 

 abdominal segment with an anterior constriction: no sclerotized air 

 tube: apical segment usually with 5 short processes surrounding the 

 spiracle sylvkolidae 



4. Mandibles opposed, moving horizontally; body cylindrical, with several 



prominent fingerlike processes around the posterior spiracles tipulidae 



Mandibles moving vertically; body not as above 5 



5. Body flattened, its surface finely shagreened ; lateral abdominal spiracles 



present ( fig. 89) stratiomyidae 



Body cylindrical, not shagreened ; lateral abdominal spiracles absent ; 

 last abdominal segment ending in 2 points vertically theeevldae 



6. Smooth maggots (figs. 14 and 83), the body conically tapering, narrow 



in front and broad and truncated behind, without prominent tubercles 

 or processes on any segment but the last ; posterior spiracles flush with 

 the posterior face of the anal segment or sunken into a concavity or 



depression 7 



Not such larvae; that is, either grublike, or with lateral or dorsal 

 tubercular or spinous processes on the segments, or with the posterior 

 spiracles at the end of 2 processes or of a respiratory tube 9 



7. Posterior spiracles deeply sunken in a rounded concavity ; inner slits 



directed away from the median line below (fig. 14, B) sarcophagidae 



Posterior spiracles flush with the posterior face of the anal segment ; or. 

 if they are sunken in a shallow slitlike concavity, the inner slits are 

 directed toward the median line ventrally 8 



8. Slits of posterior spiracles either sinuous or short and radially arranged 



(cf. figs. 65 and 68) ' muscidae (in part) 



Slits of posterior spiracles long and slender, more nearly parallel to one 

 another (cf. figs. 33 and 35) calliphoridae (in part) 



9. Larvae grublike 10 



Larvae not grublike 15 



10. Each posterior spiracle with 3 distinct slits 11 



Each posterior spiracle with numerous small openings, but without well- 

 defined slits (cf. fig. 55) 13 



11. Either nude, wrinkled larvae with the posterior spiracles separated by 



several times the diameter of each (Auchmeromyia, fig. 37) or the slits 



sinuous (CordyloMa, Stasisia, fig. 40) calliphoridae (in part) 



Spine-bearing larvae without sinuous slits in the posterior spiracle 12 



12. Pear-shaped species (fig. 50) ; spiracular slits straight and elongated. 



deeply sunk into a concavity (Dermatobia) cutebebbxdae (in part) 



Ovate species (fig. 44 i ; spiracular slits bent at the middle and in at most 

 a shallow concavity gasterophilidae 



13. Month hooks rudimentary hypoderm atidae 



Mouth hooks well developed 14 



14. Body with spines weak and located on the ventral surface only or on the 



anterior margin of each segment dorsally _ oestridae 



Body with spines or spinous plates stronger and more evenly 



distributed CUTEEEBRIDAE 



15. Body with tubercular, fleshy, or spinous processes dorsally and laterally 



on the segments * 16 



Body without such processes, at most with prolegs 18 



16. More or less cylindrical larvae with short or moderately short, un- 



branched, lateral and dorsal tubercles on the segments 17 



Flattened larvae with long filiform processes which are branched at least 

 basally and may appear feathery, on the dorsum and sides of the seg- 

 ments; posterior spiracles borne on stalks, each stalk with 4 lobes on 

 which are found the 3 slits and the button {Fannia, figs. TO and 



muscidae I in part) 



72) 



7521ir;°— 48 3 



