LVII. FAMILY 



Rather small to large, chaetophorous flies, thinly or 

 not at all pilose, usually more elongate than the Tachi- 

 nidae. Eyes of the male contiguous, or more approx- 

 imated than those of the female; pubescent or bare. 

 Front with a row of bristles on each side descending to, 

 but not below, the base of the antennae, save rarely. 

 First joint of antennae short; second usually shorter than 

 the third; third joint more or less elongate, sometimes 

 short, decumbent. Arista bare, pubescent or pilose, with 

 two or three visible joints. Face always with a well- 

 marked median depression, with a more or less distinct 

 median ridge or carina. Proboscis sometimes elongate, 

 but usually short and with bread labella; palpi never 

 with more than one joint, which is sometimes vestigial. 

 Ocelli present. Abdomen composed of four or five visi- 

 ble segments, with marginal, lateral, and usually discal 

 bristles. Legs sometimes rather stout; usually elongate 

 and slender; always bristly. All veins of wings simple; 

 basal cells large; three posterior cells present, the first 

 of \vhich is always narrowed or closed; auxiliary vein 

 distinct in its whole length. Squamae large. 



In habits and life histories, the Dexiidse closely resem- 

 ble the Tachinidse, and the distinction between the two 

 families is very difficult to make, if it is not actually 

 evanescent. The plumose or distinctly pubescent arista, 

 the presence of bristles on the dorsum of the abdomen, 

 together with the usually more slender legs, are the es- 

 sential diagnostic characters of the family. For further 

 study the reader is referred to the works of Brauer, Ber- 

 genstamm, Coquillett, Townsend and Wulp. 



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