82 



driving it from the dusted plants, although bugs confined in a box with 

 it would survive several days. 



The little Halticus pallicornis, which was this year very troublesome, 

 not only in the clover fields and vegetable gardens, on beans, cucumbers, 

 etc., but was especially destructive to asters, was also routed by having 

 this powder puffed on the under side of the leaves; the young bugs were 

 killed and the mature ones driven away. 



The Dust was further tested on a few late cut- worms, Agrotis saucia, 

 Celcena renigera, and some other species which I can not name, but 

 without much effect, as the powdered worms in the course of an hour 

 all crawled out of the deep box in which they had been confined and 

 escaped. 



All hairy larvse, as in the case of Pyrethrum, seemed insensible to its 

 effects, so also did the striped and twelve-spotted cucumber beetles and 

 other mature Coleoptera and the squash-bug. 



There are quite a number of injurious insects on which. I did not have 

 opportunity to use it, and on which I hope to experiment with it another 

 season. 



From my experience with it this season I should rank it among the 

 second-class insecticides, producing similar effects, but not quite equal 

 to the California Buhach, but still valuable for use against certain in- 

 sects on which it is not safe or expedient to employ the arsenates. 



NOTES ON PHYLLOXERA RILEYI FOR 1889. 



June 15. — Eeceived instructions through Mr. Howard to collect and 

 prepare specimens of Ph. rileyi in all its stages in fluid and in balsam 

 on microscopic slides. 



The post-oaks (Q. obtusiloba), on which the insect chiefly occurs on 

 the place, were found to be less abundantly infested than during other 

 years. The first leaves which have attained their growth and are begin- 

 ning to toughen are, however, considerably speckled with their punct- 

 ures, especially along the midrib and principal veins. Very few besides 

 the pale yellow, smooth, elongate forms are noticeable. 



Put up a number of infested leaves in alcohol reduced about 60 per 

 cent, with water. (These I afterwards learned from Mr. Howard did not 

 keep, the alcohol being perhaps too strong). I also prepared slides. 



July 22. — Have just returned from Minnesota. Sent slides on to 

 Washington. Examined leaves of post-oak around home, but found no 

 winged Phylloxera, and very little change in the specimens on the leaves 

 during the last month. 



Among other insects preying on the aphis is (Ecanthus latipennis in 

 noticeable numbers, one or more on the under side of nearly every leaf. 

 They are now nearly full-grown larvae. The puzzle is how they come 

 to be on the oaks, wlien I have never found their punctures in the twigs 

 and when some of the trees are at quite a distance from raspberry or 

 grape vines, in which they mostly deposit their eggs. 



July 29. — After driving about the country in several directions I 



