articles on the use of crude petroleum and pure kerosene for the San 

 lose scale, on experiments with summer washes for the same insect. 

 on the canker-worm on shade and forest trees, and on the Colaspis 

 root-worm, were first published in this ceport. 



The Twenty-third Report, printed in 1905, is devoted entirely 

 to injuries to Indian corn by insect species which infest the plant 

 above ground. An abstract oi the more important parts oi this vol- 

 ume was isstied in 1904 as Bulletin 95 oi the Experiment Station. 



The articles of the Twenty-fourth Report, printed in 1908, are of 

 a somewhat miscellaneous character, devoted mainly to the bill-bugs, 

 the corn root-aphis, and the chinch-bug, treated with special reference 

 to their injuries to corn: to the cottony maple scale and the elm twig- 

 girdler, treated as shade-tree insects; to experiments with insecticides 

 for the San Jose scale and the plnm-cnrcnlio ; and to the life history. 

 habits, and economic relations of the white-grubs and May-beetles. 

 With the exception oi that on the elm twig-girdler, published for the 

 first time in the report, these articles have been previously printed as 

 bulletins of the Experiment Station series— Nos. 104. 107. 108. 112. 

 and 116. 



In addition to the twelve regular reports here named, the partial 

 equivalent of such a report was printed in ISSo. under the name of 

 "Miscellaneous Essays on Economic Entomology," as an appendix to 

 the twenty-third volume of the State Department of Agriculture, the 

 principal articles in which are "The Entomological Record for 1885;" 

 "Experiments on the Codling-moth and Curculios :" "A Second Con- 

 tribution to the Life History oi the Corn Plant-louse (Aphis maidis 

 Fitch)" [mainly the corn root-aphis] ; "On the Injurious Locusts of 

 Central Illinois;" and a "Partial Bibliography of Indian Corn In- 

 sects." ddie contents of these essays are included in the following 

 index. 



The twelve reports, with their appendices, contain 2469 pages, of 

 which 2213 are the text of the articles, the remainder consisting of in- 

 dexes, tables of contents, and similar matter. These reports are illus- 

 trated by 387 cuts inserted in the text, and by 127 plates. 15 of which 

 are colored and the remainder black and white. 



Stephen A. Forbes. 

 Illinois State Entomologist. 

 Urbana. Illinois. 

 December 15. 1908. 



