NO. 3569 SOLDIER FLY LARVAE — McFADDEN 15 



2. Free cephaloskeleton present; head very poorly developed, completely un- 



sclerotized dorsally; antennae poorly developed or absent, when present 

 situated on a membranous surface; mandibles short and hooklike, usually 

 capable of protrusion much beyond the poorly developed maxillae; maxillary 



palpi rarely visible Division CYCLORRHAPHA 



No free cephaloskeleton within the head capsule, the exoskeleton of the head 

 at least dorsally indicated; antennae well developed, situated on the upper 

 surface of the lateral lobe or on the slightly arched, sclerotized frontal plate; 

 mandibles normally sickle shaped, not protruding much beyond apices of 

 the well-developed maxillae, often much shorter, maxillary palpi distinct. 



Division ORTHORRHAPHA 3 



3. Posterior spiracles situated within a terminal or subterminal cleft or chamber, 



usually concealed, or with a terminal breathing tube; pupa free or enclosed 



in last larval skin 4 



Posterior spiracles visible, situated on apical, penultimate or antepenultimate 

 segment, body not shagreened or visibly striated; pupa free 5 



4. Body 12-segmented, cylindrical, not shagreened, usually longitudinally 



striated, abdomen with a girdle of pseudopods on each segment; head 



retractUe; spiracular fissure vertical TABANIDAE 



Body 11-segmented, bristly, surface finely shagreened, without pseudopods; 

 head not retractile; spiracular fissure transverse, sometimes rather small; 

 peripneustic or amphipneustic STRATIOMYIDAE 



5. Posterior spiracles situated on penultimate or antepenultimate segment. 



THEREVIDAE, SCENOPINIDAE, MYDAIDAE, ASILIDAE, 



BOMBYLIIDAE 

 Posterior spiracles situated on apical segment 6 



6. Last abdominal segment obliquely truncate and with projecting processes; 



projecting portion of head and the flattened apical plate of last abdominal 

 segment heavily sclerotized, the former cone shaped . . XYLOPHAGIDAE 



(including Rhachiceridae and Coenomyidae) 



Last abdominal segment lacking projecting processes; projecting portion of 



head not pointed cone shaped; last abdominal segment without a heavily 



sclerotized flattened terminal plate NEMESTRINIDAE, 



EMPIDIDAE, DOLICHOPODIDAE, RHAGIONIDAE, ACROCERIDAE. 



Family Stratiomyidae 



In addition to the characters given in the key to families, stratiomyid 

 larvae may be readily distinguished from other dipterous larvae (ex- 

 cept for psychodid larvae) by the presence of calcium carbonate 

 deposits on the integimaent (see p. 7). 



Family diagnosis. — Head elongate and narrow except for ocular 

 prominences; not retractile; antennae usually located anterolateraUy 

 but varying among species; setae on dorsum of head variable; body 

 11-segmented; prothoracic segment mth functional spiracles, that 

 segment ^^ider than the head; segment posterior to prothorax either 

 parallel mth the lateral margins of the prothorax or tapering in a 

 posterior dh-ection from the second abdominal segment as in Stratiomys 

 (fig. 105); posterior spu'acles located m a transverse cleft on last 

 abdominal segment; with or mthout a fringe of hydrofuge setae; 



