790 A N INTROD UCTION TO ENTOMOLOG Y 



K. Front with grooves or a depression beneath the 



antennae, p. 853 Conopid^ 



KK. Front convex beneath the antenna;, p. 850.... 



Syrphid^ 



II. Antenna; v.-ith a dorsal arista. 



J. Head extremely large, and with nearly the entire surface 



occupied by the eyes. (Fig. 1103). p. 849. Pipunculid^ 



JJ. Head not of the type represented by Figure 1103. 



K. Wings with a vein-like thickening, the spurious vein, 



between veins R and M. p. 850 Syrphid.e 



KK. Wings without a spurious vein. 



L. Front with grooves or a depression beneath the 



antennae, p. 853 Conopid.« 



LL. Front convex beneath the antennte. p. 850. . 



vSyrphid^ 



HH. Vein Cuz appearing as a cross- vein or curved back towards 

 the base of the wing (Figs. 1096 and 1 1 15). 



I. Antennae with a terminal style or arista, p. 845. Empidid.^; 



II. Antennae with a dorsal arista. 



J. Proboscis vestigial; mouth opening small; palpi wanting 



(Botflies) Pass to Table B. 

 JJ. Proboscis not vestigial; palpi present in most cases. 

 K. Frontal suture present (Myodaria). Pass to Table B. 



KK. Frontal suture absent, p. 845 Empidid-E 



AA. Flies in which the abdomen is indistinctly segmented, and the two legs of 

 each thoracic segment are widely separated by the broad sternum. The adults 

 live parasitically upon birds, or mammals. 



B. Head sunk' in an emargination of the thorax; eyes round or oval; palpi 

 forming a sheath for the proboscis, not projecting in front of the head. p. 874. 



HlPPOBOSCID^ 



BB. Head with a fleshy movable neck; eyes wanting or vestigial; palpi pro- 

 jecting leaf -like in front of the head. p. 875 Streblid/E 



TABLE B.— THE FAMILIES OF THE MYODARIA 



A. The alulae or calypteres small or rudimentary; the subcostal vein often in- 

 distinct or vestigial, but sometimes well-preserved; vein Ri shortened and 

 often very short; thorax without a complete transverse suture; postalar callus 

 usually absent. (Subsection i — Acalyptratas). 



B. Subcosta distinctly separated from vein Ri and ending in the costa notice- 

 ably before Ri, the latter ending near or beyond the middle of the wing in 

 most cases. 



C. Oral vibrissas present and distinctly differentiated from the hairs of the 

 peristome. 



D. A distinct costal break or scar proximad of the tip of Ri near the 

 apex of Sc. 

 E. The postvertical bristles are divergent or parallel or wanting. 



F. The frontals are convergent (lacking in Hydromyza) and stand 

 nearer the median line than the fronto-orbitals. Abdominal 



spiracles in most cases in the chitin. p. 854 Cordylurid^ 



FF. The frontals absent, or if present and convergent stand in line or 

 laterad of the line of the fronto-orbitals; transverse suture in- 

 terrupted in the middle; anal vein does not reach the wing-margin; 

 cross veins in most cases approximated; abdominal spiracles in the 



conjunctivas, p. 854 Clusiid^ 



EE. Postvertical bristles convergent, costa of wing in nearly all cases 



with a row of spines projecting beyond the ciliation. p. 854 



Helomyzid.^; 



DD. Costa without a sign of a break; palpi vestigial in most species. 



E. Palpi vestigial; "front" never bristly near the antennae; anal vein 



not produced to the wing margin, p. 858 Sepsid/-, 



