Vol. XI] COLE AND LOVETT—LIST OF OREGON DIPTERA 265 



391. Dolichopus tenuipes Aldr. 



Hood River, IX-24 to X-ll (Cole); Corvallis, VM 

 (Cole). 



392. Dolichopus variabilis Loew 

 Hood River, VII-20 (Cole). 



393. Tachytrechus olympiae (Aldr,) 

 Hood River, VI-3 (Cole), M. C. Van Duzee det. 



394. Tachytrechus sanus O. S. 

 Hood River, VI-21 (Cole), M. C. Van Duzee det. 



395. Pelastoneurus vagans Loew 

 Forest Grove, IX-27 and Hood River, X-26 (Cole), 

 M. C. Van Duzee det. 



396. Pelastoneurus occidentalis Wheeler 

 Corvallis, VII-12 (Cole), M. C. Van Duzee det. 



Family EMPIDID^E 



Z 



Fig. 24. Empis poplitea Loew. 



The family is a very large one and there is a great variety 

 in form and wing venation. The prevailing colors are dull, 

 most of them brown, gray, or black. The mouth parts are 

 usually long and beak-like. The adults congregate in swarms 

 under trees or near shrubs and about brooks and dance up 

 and down in the air, hence the name "dance-flies." They 

 are predaceous, even cannibalistic, the female being "more 

 deadly than the male." Many of the flies visit flowers and 

 some species have very interesting habits. They perform 

 quaint courtship dances and carry little balloon like veils or 



