XXXII . INTRODUCTION. 



idea being, in all these desired experimeiv;;s, to reduce the bulk and expense of the 

 diluents by forcing the poisons in finer . jad fewer particles up among the plants 

 tather than down upon them, through small perforations, or (what will prove pref- 

 erable) crescent-shaped slits of various dimensions in nozzles that will bear great 

 pressure from within. 



4. Test how far, i, e., over how much l^round, on the above principles, a pound of 

 pyrethrum may be made to go and still prove effectual. 



5. Ascertain, if possible, wh^.ther the moths are not killed by sucking at the glands 

 where the plant is poisoned fxom below. 



6. Ascertain the effects of these different poisons on the eggs. 



7. Always note the difference in effect on the very young and the full-grown 

 worms. 



8. Observe well in the woods and in the neighborhood of infested fields if the 

 Aletia larva can be found feeding on any other plant, searching particularly plants 

 of the same family (Malvacecu) or that to which cotton belongs. 



9. Note and study any mites found preying on the eggs. 



10. Send me a summary of the experiments made with yeast ferment or beer mash 

 by the middle of August. 



11. Study well the influence of ants in the cotton field and in how far they prove 

 destructive to Aletia, especially to the egg or young larva. 



Respectfully, 



^ C.V. RILEY,- 



Chief U. S. E. a 



Another circular (No. 10) referred to other insects affecting either the 

 root, stem, branch, leaf, involucre, blossom or boll, but, for reasons stated 

 in the Preface, need not be repeated here. 



In the meantime the work we had left unfinished in the Department, 

 together with some additional work done by Mr. William Trelease under 

 direction of our successor, had been prepared for publication, and was 

 issued in August, 1880, by Professor Com stock as author, under the 

 title: Eeport | upon | Cotton Insects | prepared | under direction of the 

 Commissioner of Agriculture in pursuance of an Act of Congress ap- 

 proved June 19, 1878 | By | J. Henry Comstock | Entomologist to the 

 Department of Agriculture | Washington | Goverument Printing Office 

 I 1879 I . This is referred to in the following pages either as the ^' De- 

 partment Eeport on Cotton Insects '^ or as " Comstock's Cotton Insect 

 Keport." 



On July 1, 1881, the U. S. Entomological Commission was transferred 

 by previous act of Congress from the Department of the Interior to the 

 Department of Agriculture, and we were soon thereafter asked to re- 

 sume the position, which we had resigned two years previously, of ento- 

 mologist to this last Department, under whose auspices the investiga- 

 tion has since been carried on. The work in 1881 and 1882 was chiefly 

 devoted to the preparation of the present report and to the testing and 

 perfecting of the machinery that had been devised, the Cotton Conven • 

 tion held in the autumn of 1881 at Atlanta, Ga., offering a favorable 

 opportunity, and much time having been given to the preparation of 

 an exhibit of such machinery, which the Commissioner desired should 

 be made there. Such further experiments as were made with insecti- 



