— 115 — 



Thti writings of Loew, Schiner, Gerstacker, Osten-Sackt-n and Biauer 

 havebeen especially studied in the preparation of this paper. 



Empodlum developed pulvilliform, pulvilli present. Without distinct bristles 

 ^diptera eremocbaeta O. S. ). Basal cells of icings large. Third joint of antenncK seg- 

 mentated or annulated. Tegidce small or rudimentary. Proboscis not adapted for 

 piercing. Males holoptic or dichoptic* . 



I. — Tibice wholly without spurs; veins usually crowded anteriorly 



STRATIOMYIDAE. 

 Tibiae more or less spurred ; the costal vein encompasses the whole wing; two 



sub-marginal and five posterior cells always present 2 



2. — All the tibise with spurs 3 



Front tibiae without spurs 4 



3. — Thiid joint of antennae not acute at tip, or, if so, the sculellum with spines on 



Its border XYLOPHAGIDAE. 



Third joint^cute; palpi cylindrical; scutellum without spines.. *Arthropeas, Lw. 



4. — Fourth posterior cell closed. {Macroceromys Bigot) Subula, Meig. 



Fourth posterior cell open 5 



5. — Face projecting on each side into a rounded conical protuberance, thickly cover- 

 ed with hair *Glutops, Burgess. 



Face with two deep, diverging furrows, running from the base of the antennae to 

 the oral margin ''Nov. gen." O.S. 



XYLOPHAGIDAE, 



Species of moderate or large size, more or less elongated, thinly 

 pilose, or nearly bare. Ocelli present. Antennae elongate, third joint 

 annulated or segmentated, never with a differentiated style or bristle. 

 Veins of the wings distinct, not crowded anteriorly, third longitudinal 

 vein furcate; five posterior cells. Abdomen with seven or eight visible 

 segments. All the tibiae with spurs at the tip. 



The flies are usually found about trees, where they feed upon sap, 

 or about decaying logs, and are often mistaken for ichneumonids. 



I. — All four posterior veins arise from the discal cell; head small; scutellum with 



spines Ccenomyia, Latr. 



The last posterior vein arises from the second basal cell; head not small; scutel- 

 lum without spines 2 



2.— Fourth posterior cell closed; third joint of antennae much elongate, composed of 

 numerous distinct divisions, often pectinate; eyes emarginate near the antennas 



Rhachicerus, Hal. 

 Fourth posterior cell open ; third joint of antenna composed of eight annuli, in- 

 distinctly separated Xylophagus, Meig. 



* I propose this term as tiie antithesis of holoptic. • 



