301 



favorable conditions are found in the semi-arid region of the south- 

 western central portion of the United States. 



(3) The cause of a poor yield of sugar in sorghum of high polari- 

 zation is due to the presence of some form of carbohydrates or other 

 organic body, exercising a higher melassigenic poAver than invert 

 sugar or any form of levulose and dextrose. 



(4) The tendency of selected seeds from rich canes to produce a 

 uniform (.-rop of liigh jjohirizing canes under favorable conditions of 

 light and heat is established. 



(5) The possibility of developing, from existhig varieties, a per- 

 manenth' improved crop, capable of cultivation for manufacturing 

 purposes, is fully assured. 



(G) The prospects of doing this with two or three of the standard 

 varieties is more promising than dependence on an experimental or 

 fortuitous development of a new variety free from the faults inherent 

 in sorghum. 



In brief, the conditions of success in sorghum growing for sugar are 

 (1) a climate thoroughly adapted to the plant; (2) scientifically 

 tested seed of the most api^roved varieties; (3) much more careful 

 cultivation than is usually bestowed on corn. 



DIVISION OF ENTOMOLOGY. 



BULLETIN No. 21. 



Natural ene:mies of the fluted scale in Australia, A. Koebele 

 (pp. 32). (illustrated). — A report of investigations on the natural 

 enemies of the fluted scale {Icerya jnircliasi^ Maskell), made in Aus- 

 tralia during 1888-89, under the authority of the United States Com- 

 missioner of Agricidture. As the result of these investigations a 

 number of species of insects which prey ujoon the fluted scale have 

 been introduced into California, and one of these species seems 

 already quite at home there. In the introduction to this report Pro- 

 fessor Riley writes as follows regarding this insect : 



One of the insects imported, viz, the Cardinal A^edalia {Vedalia cardinalis, 

 Mulsant), has multiplied and increased to such an extent as to rid many of the 

 orange groves from Icerja and to promise immunity in the near future for the 

 entire State of California. In fact, the rapid multiplication and the effective 

 work of this little beetle are almost incomprehensible until we come to consider 

 its power of increase in a climate like that of Southern California, where there 

 is scarcely any cessation in its activities. [For details regarding the Vedalia, 

 see Insect Life, Vol. II, No. 3, pp. 70-74.] The period from the laying of the 

 eggs until the adults again appear occupies less than thirty days for the Vedalia. 

 At this rate of increase, calculating that thi-ee hundred eggs are laid by each 

 female, and that one-half of these produce females, it will readily be seen that 

 in six months the offspring of a single female beetle may, under favorable cir- 

 cumstances, amount to over twenty-two trillions. So far it has not been noticed 

 to prey upon any other insect than the fluted scale, a fact which accounts some- 

 what for its exceptionally rapid work, and renders the outlook extremely 

 encouraging. 



18493— No. 5—05 m 5 



