747 



The results of the investigatious tliiis far made are summed up by 

 Professor Riley iu an iutroductioa to the bulletin, as follows: 



It transpires that the ravages of tho holl-wonu Iiavo been ovorcsti mated, and that 

 while from 20 to ;?0 per cent of the bolls are damaged in an average season iu Missis- 

 sippi, only about one third of this damage is done by this insect. Several other 

 species which do work somewhat similar to that of the boll-worm are treated in this 

 report. Some new food plants have been found, and a careful study has been made 

 of the habits and life history, which ai'e hero treated with more care and detail than 

 has heretofore been given to the subject. Two new parasites have beeu discovered, 

 and observations have been made which show that the egg parasite {Trichogramma 

 prctiosa, Riley) is an extremely important factor iu the economy of this insect, as it is 

 also in that of the cotton worm {Aletia xjilma, Say), and the grass worm or fall army- 

 worm {Lapliygma fntgiperda, Smith and Abbott). A careful count shows that 84 per 

 cent of the eggs were destroyed by this useful parasite. All of the old remedies 

 have once more beeu tested, and the use of corn as a trap crop is again shown to be 

 one of the most satisfactory means of protecting the cotton crop. The old subjects 

 of attracting the moths to lights and poisoned sweets have once more been carefully 

 considered, and my former conclusions have been confirmed, that there is little to bo 

 hoped for from either of these methods. The pyrethrum experiments, from which 

 I had much hope, have not proved very favorable, while experiments with a large 

 series of other vegetable insecticides have given no practical results as yet. 



The experiments with contagious diseases can not be reported upon in any detail 

 at the present time, but a large number of cultures of several diseases of the 

 imported cabbage-worm, the bronzy cut-worm, and of two other Noctuids have beeu 

 secured and carried through the winter. What may prove to be a specific disease of 

 the boll-worm has also been discovered, and cultures have been obtaiiied. It appears 

 from the few experiments made that the boll-worm is probably suscejitible to tho 

 cabbage-worm disease, but positive statements can not be made until these experi- 

 ments are confirmed by those of another season. A bacteriological laboratory has 

 been established at Shrevenort, Louisiana, and has been well fitted out with the 

 necessary apparatus, so that work in this direction the coming season will not be 

 hampered, except in the case of an unexpected paucity of boll- worms. 



CiRCULAE, No. 1 (Second Series), May, 1891. 



Some of the more important insecticides (pp. 7). — Condensed 

 information concerning kerosene emulsion, resin washes, London purple, 

 Paris green, and white arsenic, including formulas for the preparation 

 of these insecticides and directions for their application. 



DIVISION OF CHEMISTRY. 



Bulletin No. 29. 



Experiments with sorghum in 1890, IT. W. Wiley (pp. 125).— 

 This contains a report on studies on the separation of sugar from 

 sorghum juices, with si)ecial reference to the use of alcohol for this 

 purpose (See Experiment Station Record, Vol. II, p. 469); the composition 

 of the bodies precipitated by alcohol from sorghum sirups ; results of 

 the operations of tho sorghum-sugar factories at Attica, Fort Scott, 

 Topeka, Conway Springs, and Medicine Lodge, Kansas, in 1890, as 

 shown by chemical control; general results of manufacturing work; 



