Dec, 1922.] JOHANNSEN : StRATIOMYIID LaRV.E. 143 



E. A pair of hooks on ventral posterior margin of segment eleven 

 only ; tip of antenna produced almost as far cephalad as the 



beak Sp. A. ' 



EE. Hooks on venter of both segments ten and eleven. 

 F. One pair of stout hooks on ten and eleven. 



G. Length of full-grown larva over 15 mm, . . pilimanus. 



GG. Length of full-grown larva 12-15 rnm. vertebrata. 



FF. One pair of stout hooks on 11, four or more on 10. 



G. Four hooks on 10; antennae about four times as long 



as broad, tips produced beyond tip of beak .... Virgo. 



GG. Four hooks on 8, six on 9 and 10, and two on 11 ; 



antennae stouter, not produced to tip of beak... Sp. B. 



CC. Antennae placed dorsally, remote from the margin ; each abdominal 



segment except the last, before its middle on ventral side, with a 



transverse row of short, stout spines Euparyphus. 



D. Ventral hooks of penultimate segment large, over half as long 

 as the segment itself; the last instar with anterior spiracles on 

 elongate processes (figs. 5, 6, 7, 13, 15) ; length 9 mm. brevicornis 

 DD. Ventral hooks of penultimate segment much shorter. 



E. Ventral hooks distinctly longer than the five straight, stout 

 spines on the same segment ; median process (beak) of the 

 head not produced as far cephalad as the mouth parts (figs. i. 



4, 12); length 13 mm greylockensis. 



EE. Ventral hooks but little if any longer than the two straight, 

 stout spines before fhe middle of the same segment (figs. 2, 



3); length 10 mm tetraspilus. 



BB. No ventral hooks on the penultimate segment. 



C. Posterior spiracular chamber on the dorsal side of the terminal 

 segment, this segment emarginate and armed with four to six long 

 marginal setae ; fringe of plumose hairs short, not, or scarcely pro- 

 duced beyond the markin of the segment (fig. 18). .. Nemotelus. 

 CC. Posterior spiracular chamber at the apex of the segment; hair 

 fringe long. 

 D. Terminal abdominal segment not much longer than broad 



(fig. 21) Oxycera. 



DD. Terminal abdominal segment much longer than broad 



Stratiomyia. 

 E. Terminal segment about five times as long as its width at 



base (fig. 9). norma. 



EE. Terminal segment not over three times as long as its width 

 at base. 

 F. Penultimate abdominal segment about three fourths as 



long as the terminal segment normula. 



FF. Penultimate segment about five eighths as long as the 

 terminal segment meigenii. 



