296 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



608. Oncomyia modesta Will. 



Hood River, VI-2 to VI-25 (Cole). This is a very com- 

 mon species at Hood River and is apparently parasitic on 

 a bee, determined by Mr. Crawford of the National 

 Museum as Halictus ligatus Say. The flies are often taken 

 on flowers and three specimens had the triangulin stage of 

 some Meloid beetle attached to them. The females perch 

 on grass stems or flowers near the underground colony of 

 bees and swoop down on the unsuspecting pollen gatherers 

 as they approach their burrows. The fly and bee usually 

 go tumbling on the ground together, but the fly does not try 

 to sit on the bee, and always manages to get away in a great 

 hurry, returning to her observation post, there to clean off 

 some of the dust and watch for more victims. It is amusing 

 to watch them follow the bee with their eyes as it looms up 

 on their horizon. They strike so quickly that their 

 flight can scarcely be followed. The bees make no attempt 

 to drive them away, but when attacked make frantic efforts 

 to escape. 



609. Myopa longipilis Banks 



Corvallis, IV-22; Forest Grove, IV-12 (Rockwood) ; 

 Hillsboro, IV-1 (Cole). 1916, Ann. Ent. Soc. Amer., IX, 

 p. 197. 



610. Myopa melanderi Banks 



Hood River, V-10 and 16 (Cole). 1916, Ann. Ent. Soc. 

 Amer., IX, p. 197. 



611. Myopa rubida (Bigot) 



Hood River, V-5 to VI-24 (Cole); Mosier, VI- 14 

 (Childs and Cole) ; Forest Grove, IV-12 (Cole) ; Wheeler 

 Co., VI-15 ; Corvallis, VI-3. This species is quite common in 

 the Hood River Valley in the spring and early summer, fre- 

 quenting various flowers. 



612. Myopa seminuda Banks 



Corvallis, IV-12 (Cotypes). This species is very near 

 rubida and may be only a variety of that species. 1916, 

 Ann. Ent. Soc. Amer., IX, p. 198. 



