373 

 Wirth and Stone: Diptera 



To go into any great detail in the special termi- 

 nology of characters used in the keys and diagnoses 

 is impossible here. We hope that reference to the 

 figures will be sufficient to use the keys in most 

 cases. Torre-Bueno's (1937) glossary is almost 

 indispensable and should be consulted freely. If 

 available to the student, the following references 

 should be used to supplement our keys: Curran (1934) 

 and Brues and Melander (1954) for keys and illustra- 

 tions to the adults; Malloch (1917), Johannsen (1934- 

 1938), Hennig (1948-1952), Chu (1949), and Peterson 

 (1951) for keys and illustrations to the immature 

 stages. Crampton's (1942) review in the Diptera of 

 Connecticut of the external morphology of adult 

 Diptera is extremely helpful. We have followed (fig. 

 14:1,2) the Tillyard modification of the Comstock- 

 Needham system of designating the wing venation, 

 outlined in the same volume by Friend (1942). Refer- 

 ences to the special literature of each family will 

 be found at the end of each family section; however, 

 to conserve space when such references are to general 

 Diptera works, the reader is referred to the end of 

 ( this section for the complete citation. 



Keys to the Families of Aquatic Diptera 

 Adults 



1. Antenna usually longer than the thorax (figs. 14:3a, 

 14:165, 14:36), consisting of a flagellum of 6 or more 

 similar free segments, with 2 enlarged basal segments 



2 



— Antenna usually 3-segmented, 3rd with a style (fig. 

 14:44^) or arista (figs. 14:2e,/> 14:54i; 14:63a) or with 

 more or less distinct annulations (fig. 14:44a',e) .... 13 



2. Mesonotum with a V-shaped transverse suture begin- 

 ning on each side in front of root of wings, the pointed 

 middle part close to the scutellum (fig. 14:3a); female 

 with a conical ovipositor (TIPULOIDEA) 3 



— Mesonotum without a V-shaped suture; if a transverse 

 suture present it is interrupted in middle and there 

 are less than 9 veins meeting wing margin (figs. 

 14:150,6; 14:19t,;'; 14:28a; 14:29t) 5 



3. Only 1 anal vein reaches wing margin (fig. 14: la) 



4 



— Two anal veins reach the wing margin (fig. 14:3a) 



TIPULID AE 



4. Second and 3rd veins each with 2 branches (radius 

 5-branched) (fig. 14:1a) TANYDERIDAE 



— Second and 3rd veins with only 3 branches reaching 

 the wing margin (radius 4-branched) (fig. 14:8/) .... 



LIRIOPEIDAE 



5. Wing membrane with a secondary venation due to 

 creases from folding of wing in the pupa (fig. 14:1/) 



6 



— Wings without an extensive secondary venation .... 7 



6. Wings large, with fine hairs, true veins almost absent 

 but an elaborate fanlike development of secondary 

 folds present; male antenna exceedingly long, 6- 

 segmentea (fig. 14: 12) DEUTEROPHLEBUDAE 



— Wings with we 11 -developed primary veins, the secondary 

 folds forming a delicate network like spider webbing 

 (fig. 14:1/) BLEPHARICERIDAE 



7. Costa continuing around wing margin, although often 

 weaker along hind margin of wing 8 



— Costa ending at or near the wing tip 11 



8. Seven longitudinal veins reaching wing margin (fig. 

 14:43a) THAUMALEIDAE 



— At least 9 veins reaching wing margin (figs. 14:16c; 

 14:186) 9 



Fig. 14:1. Wings of Diptera. Venation labeled according to 

 Tillyard modification of Comstock-Needham system: A, anal; 

 C, costa; Cu # cubitus; M, media; R, radius; Sc, subcosta; hm, 

 humeral, a, Tanyderidae, Protop/osa; b, Sirnuliidae, Simulium; 

 c, Tendipedidae, Procladius; d, Phoridae, Dohrn/'phora; e, 

 Empididae, Empis; f, Blephariceridae, 8/ephar/cero; g, Culicidae, 

 Aec/es; h, Rhagionidae, Chrysopi /us; i, Dol ichopodidae, Do/i- 

 chopus; j, Syrphidae, Syrphus; k, Muscidae, Musca (Friend, 1942). 



9. Veins and body lacking scales; subcosta ending in 



costa at or bevond middle of wing (fig. 14:186) 



* DTXIDAE 



— Veins, including hind margin of wing, very hairy or 

 scaly; body and legs hairy or scaly (fig. 14:9a) 10 



10. Wings short, broadly ovate or pointed, cross veins 

 absent except near base of wing (fig. 14:9a); wings 

 held rooflike over body when at rest PSYCHODIDAE 



— Wings longer and narrow, not held roof like over the 

 body (fig. 14:15a,6) CULICIDAE 



11.. Wings with anterior veins thick, others very weak, 

 5th longitudinal vein (mediocu'oitus) forked at the base, 

 not petiolate (fig. 14:196) SIMULIIDAE 



— Anterior veins not greatly thicker than other veins, 

 5th vein usually forked near middle of wing and peti- 

 olate 12 



12. Fourth vein (anterior media) not forked; mouth parts 

 not fitted for piercing; postscutellum usually with 

 median longitudinal furrow or keel . .. TENDIPEDIDAE 



— Fourth vein forked; mouth parts fitted for piercing; 

 postscutellum rounded, without median furrow or keel 



HELEIDAE 



13. Tarsi with 3 nearly equal pads under tarsal claws 

 (empodium developed pulvilliform, fig. 14:2a") 14 



— Tarsi with 2 pads under claws (empodium hairlike or 

 absent, fig. 14:2c); 3rd antennal segment never annulated 



16 



