TABLE OF CONTENTS. Yll 



horticultural societies, 21. Efforts leading to the resumption of ento- 

 mological work by the State of New York, 21. Movements elsewhere for 

 State entomologists, 21 ; economy of their employment by each of the 

 States, 21 ; their present number too small for the work to be done, 22. 



The Acquisition of Life-histokies of Insects 33 



Desirability of acquaintance with all the stages of insect life, 23. Im- 

 portance of a knowledge of the larval form, 22. Study now given to 

 life-histories, 22. Value of such study, 22. Mr. W. H. Edwards' 

 studies, 22. Studies of our moths, 22. Coleopterous larvift studied by 

 F. W. Schaupp and Dr. Horn, 22. 



Formation of Biological Collections 33 



In what these collections consist, and their arrangement, 23. The bio- 

 logical collection of the New York State Agricultural Society, 23. The 

 collection of the Entomological Division of the Department of Agricul- 

 ture, 23. The deposit of the general collection of Prof. Riley in the 

 United States National Museum, 24 ; its biological material, 24. The un- 

 equaled biological collection of the Museum of Comparative Zoology, at 

 Cambridge, 24; Agassiz' appreciation of entomological science, 24 ; labors 

 of Dr. Hagen, 24; extent of the collection, 24 ; its appreciation by 

 students, 24. 



DISCOVERY OF VALUABLE INSECTICIDES .....35-55 



Their recent discovery an evidence of progress in economic investiga- 

 tions, 25. Discovery of the insecticidal properties of Paris green, 25. 

 Use of Pyrethrum extended from household pests to field and garden in 

 sects, 25. First introduction of London purple, 25. Its subsequent use, 



25. Employment of oils for destroying insect life, 25. 



I'Aius Green as an Insecticide 3G 



Its popularity the result of its need in potato culture, 26. Its value in 

 destroying the Colorado potato-beetle, 26. Amount of combined arsenic, 



26. Enormous demand for it, 26. Adulteration, 26. Different methods 

 of use, 26. Diluents, 26. Arrangements for mixing, 26. The dry mix- 

 ture, 26. The best diluent and its proportion, 26. Plaster of Paris as a 

 diluent, 27. Proportions of the wet mixture, 27 : its preparation, 27. 

 Advantages of the wet mixture, 27. Application of the powder, 27. A 

 convenient dustings-box, 27. Precautions necessary, 27. Various dusting 

 machines, 28. Cost of the dry application, 28. Application of the liquid, 

 28. Simple appliances ordinarily needed, 28. Sprinkler for use in fields 

 illustrated and described, 28. The Hydronette for use upon trees, de- 

 scribed and figured, 29 ; also, the Aquaject, 80. The Whitman Fountain 

 pump, 30. A desirable nozzle for scattering the liquid, 31. Sprinklers 

 devised for cotton plantations, 31. No danger in properly using the 

 poison, 31. Precautions desirable to be taken, 31. Potatoes treated with 

 Paris green not poisonous or unwholesome, 32. Change undergone by 

 Paris green in the soil, 32. Experiments upon its efi'ect upon plant- 

 growth, 32. Large amount that maybe applied before affecting plant- 

 growth, 32. Is not absorbed by plants, 32. Insects that may be destroyed 

 by it, 32. Useful against several potato insects, 32 ; also, the white- 

 marked tussock-moth, canker-worm, basket-worm, insects on the Virginia- 

 creeper, the army-worm, etc., 33. General conditions permitting its 

 iise, 33. 



