INTBODUCTIQR 



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 Eed Scale of California (Aspidiotus [Aonidia] 

 aurantii 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 purcJiasi, 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 Eed 

 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 Yedalia 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 leaf-hoppers injuring forage plants. This is a comparatively 

 new and important field of investigation. 



Professor Webster continues his studies of grain insects 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 aud also the histories 

 of two interesting Saw-flies. 



