INTRODUCTION. 
This bulletin comprises the reports of the field agents of the Division 
of Entomology which were necessarily omitted from the annual report, 
in which it has been our previous custom to publish some or all of 
them. . 
Mr. Coquillett has reported upon several phases of his work, and we 
print here only the portion relating to the experiments which he made 
in the destruction of the Red Scale of California (Aspidiotus [Aonidia] 
aurantit Maskell) by the use of washes. <A portion of his report re- 
lating to experiments with gas treatment for this scale insect, resulting 
in the great cheapening of the use of this process, has been printed in 
the double number of INSEcT LIFE for January and February, 1890. 
Another section of his report relating to the attempted colonization of 
the insects preying upon Icerya purchasi, imported by Mr. Koebele from 
Australia, has also been published in part in INSECT LIFE for October, 
1889, and the remainder is reserved for future use. The experiments 
with washes were undertaken with a view of presenting a practical 
illustration of their utility to the fruit-growers of southern California 
who had apparently ignored the previous results obtained and pub- 
lished in our reports for 1886 and 1887. These late experiments were 
performed by instruction of Assistant Secretary Willits, and the Red 
Scale was particularly chosen on account of its importance as a pest, 
and for the further reason that the Fluted Scale seems at present to re- 
quire no further experimentation, since the Vedalia is overcoming it so 
rapidly. 
Professor Osborn, in obedience to instructions, has taken up the 
study of insects injurious to grasses in addition to his regular work 
upon the insect parasites of domestic animals, and reports at this time 
upon the leat-hoppers injuring forage plants. This is a comparatively 
new and important-field of investigation. 
Professor Webster continues his studies of grain iusects and reports 
here upon certain points connected with the economy of a few well- 
known pests. 
Miss Murtfeldt sends in a general report upon the insects of the sea- 
son in eastern Missouri, brings out a number of interesting facts, and 
gives the life history of a beetle injuring Spinach and also the histories’ 
of two interesting Saw-flies. 
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