DIPTERA. 131 



SYNOPSIS OP FAMILIES. 



Bombyliidae: discal adjacent to last posterior, and each about equal to 

 second basal cell. 



Tachinidae: arista bare and calypteres large. 



Asilidae proboscis horny and face densely bristly below. 



Syrphidae: spurious vein present. 



Tipulidae: thorax with v-shaped suture dorsally. 



Empidae: discal and last two basal cells about equal in length and in dis- 

 tance from hind edge of wing. 



Dolichopidae: discal and second basal cells confluent and first basal cell 

 very short. 



Tabanidae: last fork of primary vein spreading widely. 



Culicidae: veins clothed with scales. 



Mycetophilidas: antennge longer than thorax. Psychodidse; body and 

 wings densely hairy. Cecidomyidae: tibiae without spurs. Chironomidas: 

 veins very feeble on hind half of wing. 



Stratiomyidae: basal cells more than twice as long as discal cell. 



Trypatidas: auxiliary vein absent. Borboridae: hind metatarsi shorter 

 than other joints and thickened. Ephydridae and Oscinidae: discal and 

 second basal cells confluent and third basal absent, the latter consisting of 

 pale colored flies. Agromyzidae, Geomyzidae and Drosophilidae: with oral 

 vibrissas, the first with hind cross vein before middle of the wing, the last with 

 long plumose or pectinate antennae. 



Threvidae: five posterior cells. Leptidae and Cyrtidae: three pads between 

 the claws, the latter with the head very small. 



Muscidae: calypteres large. CEstridae: oral opening small. Anthomidae: 

 first posterior cell wide open. Sarcophagidae: with outer half of arista bare 

 Dexidae: base of abdomen bristly. 



Ortalidae: antennae with dorsal arista. Pipiculidae: head nearly as large as 

 thorax. Conopidae: with long slender proboscis. Sepsidae, Scatophagidae 

 and Helomyzidae: with oral vibrissse, the last with costa pectinate, the 

 second front bristly near antennae. Micropezidae: head subspherical. Sap- 

 romyzidae and Sciomyzidae: first two abdominal segments not at all coalesc- 

 ed, the abdomen of the latter elongate. 



Puiicidae: wingless. Sarcopsyllidae: labial palpi only one jointed. 



Simuliidae: heavy veins near costa only. Phoridae: antennae apparently 

 only one or two jointed. 



Blepharoceridae: wings marked by a net of fine lines. 



Midaidae. Bibionidae: antennae many jointed. Apioceridae and Scenopin- 

 idae: head not hollowed out between the eyes, the latter with only three 

 posterior cells. 



The fleas and winged bird lice specialized as parasites on vertebrates 

 are generally separated from other flies tho retained within the order. The 

 more typical files have generally been classified in one of two ways, by the 



