the top of his head. Although I do not know whether this is a biting fly, I suspect that it is the cause of the sudden, frantic leaps and yips which I have noted with nearly all of the thrashers here. Fortunately I secured one from a live sparrow which was offered to Rhody, and doubtless they will be able to classify it at the Universi- ty. Apparently it is a common parasite on wild birds. The sparrow had several on him, underneath his feathers. I thought B had finished his, but occasionally I glimpse the sheath of a pin-feather on his wings. I have been unable to see whether the imperfect feather on his left wing--noted last year about this(?) time--has been replaced. Bb is getting so smooth that it is necessary to scrutinize him pretty carefully to be sure of his identity. He is getting grayer about the head. I suspected him of full song yesterday, but can not be sure. (By a curious coincidence, just now --10:25 A.M.--he started to sing undersong. He is about 75 feet away digging diligently . An Anna humming-bird is near him singing: Be-zit, be-zee, zit, zit, yurk, beévoor! interminably). 12:30 P.M. Whatever it is that bites B and Bb is particularly act- ive just now. Both B and Bb at the oval lawn , during the past few minutes, have even tried to run away from it after jumping and prod- just ding frantically. As noted with Greenie, both of them have frozen in rigid, expectant attitudes at my feet waiting to be bitten . The attack, as gauged by the point where they immediately search themselv selves, may occur any place and they seem unable to catch their tormentors. Sometimes I have wondered whether it might not be an internal parasite, especially since the worm was found in Little Greenie's intestines, but doubt if such is the case. 1:35 P.M. B has just been sitting alongside me waiting for another attack and saying: over and over again: