Family EMPIDIDAE 



(Figs. 14:50, 14:51) 



Adult empidids or "dance flies" frequent moist sit- 

 uations and all are predaceous on smaller animals. 

 Some species live along seashores, feeding upon 

 small invertebrates at the water's edge. The unique 

 mating habits of the adults have been described by 

 many observers. During their mating swarms or dances, 

 the males of some species offer food to the females, 

 and still other males build a .characteristic silvery 

 balloon to lure the female. 



The immature stages of most groups, where known, 

 breed in damp earth, decaying wood, or vegetation, 

 usually in wooded areas, or under bark of trees. In 

 the subfamilies Clinocerinae and Hemerodromiinae, 

 however, all the known larvae are aquatic. In fact 

 all the known aquatic empidids belong here. The 

 larvae of this family are predators and resemble those 

 of the Dolichopodidae in many characteristics. They 

 differ mainly in the shape of the last body segment 

 which is rounded caudad in the terrestrial forms, or 

 has tapered processes in the aquatic larvae, (figs. 

 14:50d,n; li:51b,d), rather than concave and peri- 

 pherally lobed. The aquatic larvae also possess 

 well-developed ventral pseudopods similar to those 

 of Atherix. The pupae (figs. 14:50;,£; l4:51o,c) lack 

 the elongate prothoracic spiracular organs, the body 

 is provided with rows of well developed spines, and 

 in some genera there are several pairs of very long, 

 ventrolateral hairs or filaments. 



Keys to the North American Genera of Aquatic Empididae 

 Adults 



1. Thorax elongate, not highly arched, mesopleura ob- 

 liquely longer than vertically high; front coxa always 

 longer than posterior ones (fig. 14:50m); anal angle of 

 wing not projecting; 2nd basal cell closed apically 

 (fig. 14:506) 2 



— Thorax not elongate, the mesopleura distinctly higher 

 vertically than obliquely long; front coxa not elongate; 

 anal angle of wing more or less projecting (EMPI- 

 DINAE, OCYDROMIINAE, and HYBOTINAE); or the 

 discal cell united with the second basal cell and all 

 veins extending straight to wing margin (TACHY- 

 DROMIINAE) Not aquatic 



2. Anterior pair of legs far from the middle pair, raptorial 

 (fig. 14:50m) (HEMERODROMIINAE) 3 



— Anterior legs not distant from the middle pair and not 

 raptorial (CLINOCERINAE) 9 



3. Antennal style shorter than 3rd segment (fig. 14:502); 

 thorax without discal macrochaetae, metapleura bare; 

 3rd vein normally forked; anal cell when present broader 

 toward apex, the anal cross vein usually straight (fig. 

 14:50m) 4 



— Antennal arista more than twice as long as 3rd antennal 

 segment; thorax with some discal macrochaetae; meta- 

 pleura with some fine setulae; 3rd vein simple; anal 

 cell with parallel sides and more or less rounding cross 

 vein, subequal to the small second basal cell .... 



4. Humeral cross vein absent, subcosta fused with costa 

 close to base of wing; 1st vein short, ending before 

 middle of wing; eyes nearly or quite contiguous on 



457 

 Wirth and Stone: Diptera 



face (fig. 14:50m) Hemerodromia Meigen 



— Humeral cross vein present, subcosta separate from 

 costa; 1st vein ending at or beyond middle of wing, 

 anal cell complete or at least anal vein weak; eyes 

 separated on face 5 



5. Discal cell complete Chelifera Macquart 



— Discal cell incomplete, fused with either 2nd basal or 

 3rd posterior cell 6 



6. Second posterior cell petiolate; front femora more or 

 less spinose; 1st vein ending beyond middle of wing, 

 2nd vein not shortened 7 



— Second posterior cell sessile; front femora weak and 

 not strongly spinose, front tibia pubescent; 1st vein 

 ending at middle of wing, 2nd vein usually short .... 



Neoplasia Coquillett 



7. Discal cell fused with 3rd posterior cell with anterior 

 cross vein beyond end of 2nd basal cell; style micro- 

 scopic Thanategia Melander 



— Discal cell fused with 2nd basal cell, with anterior 

 cross vein much before end of cell; style 1/3 as long 

 as 3rd antennal segment Metachela Coquillett 



8. Discal cell complete, emitting 3 veins apically; anal 

 cross vein rounding the anal cell . .Chelipoda Macquart 



— Discal cell open, the posterior cross vein absent and 

 the 4th vein acutely forked; anal cell truncate, slightly 

 shorter than 2nd basal cell. . . . Phyllodromia Zetterstedt 



9. Third antennal segment remarkably lengthened, strap- 

 like, and without evident style 10 



— Third antennal segment not remarkably long (fig. 14:50a) 

 11 



10. Antenna inserted above the middle of the head; a row 

 of acrostichals present Niphogenia Melander 



— Antenna inserted below the middle of the head; acro- 

 stichals absent Ceratempis Melander 



11. Antenna inserted at the middle of the head, the 3rd 

 segment with a short style which terminates in a 

 bristlelike segment; face not constricted from the 

 cheeks by a suture; 3rd vein not furcate 



Boreodroma Coquillett 



— Antenna inserted above the middle of the head, the 

 3rd segment usually with a long arista; oral margin of 

 the cheeks with a more or less distinct incision or 

 suture extending toward the eyes (fig. 14:50a) 12 



12. Third vein simple 13 



— Third vein branched (fig. 14:506) 14 



13. Anal cross vein greatly reflexed, nearly parallel with 

 axis of wing; costa with setulae; 1st vein ending before 

 middle of wing; front femora with flexor thornlike 

 spines Oreothalia Melander 



— Anal cross vein perpendicular to the axis of the wing; 

 costa without setulae; 1st vein ending beyond the 

 middle of wing; femora not spinose 



Heleodromia Haliday 



14. Fourth vein arising near base of anal cell, the 2nd 

 basal cell as long as anal cell; subcosta obsolete 

 apically Proclinopyga Melander 



— Fourth vein arising near the end of the basal 3rd of 

 anal cell, the 2nd basal cell therefore shortened; sub- 

 costa ending in the costa (fig. 14:506) 15 



15. Proboscis as long as the head, slender, pointed, rigid, 

 without labe 11a; cheeks rostriform 



Roederiodes Coquillett 



— Proboscis usually short, thick, fleshy, not inflexed; 

 cheeks usually narrow (fig. 14:50a) 16 



16. Head articulated to the thorax high up on the occiput, 

 extending obliquely forward; legs yellowish 



Dolichocephala Macquart 



— Head articulated nearer the center of the occiput, hang- 

 ing vertically (fig. 14:50a); legs usually wholly or in 

 part blackish 17 



8 17. Face separated from the lower occiput by an incision 

 on the cheeks that extends to the eye; face not de- 

 scending beneath the eyes; no acrostichals 



Clinocera Meigen 



