UPON SCALE-INSECTS. 13 



species of fungi has been mentioned incidentally from time 

 to time in systematic treatises. References to these occur 

 in the descriptive part of this paper. 



Within the last twelve years some of the Experiment 

 Stations of the Agricultural Department of the United 

 States of America have been interesting themselves in these 

 fungi, especially from the economic standpoint. Webber* 

 in 1897 in an important paper on the " Sooty Mold of the 

 Orange and its Treatment" describes certain entomogenous 

 fungi which indirectly can assist in the removal of " sooty 

 mould" (Meliola) by attacking the coccids which excrete 

 the honey-dew. It is upon this sugary excretion that the 

 Meliola grows clogging the leaves and spoiling the appear- 

 ance of the fruit. So not only does the scale-pest inflict 

 direct damage on the orange trees by sucking its sap, but 

 indirect harm as well by encouraging this unsightly Meliola. 

 Webber chiefly deals with a fungus new to science and 

 named by him Aschersonia aleurodis, parasitic upon the 

 mealy wing or white fly {Aleurodes^ citri) which is res- 

 ponsible for much sooty mould on the orange in Florida. 

 Other species of Aschersonia are mentioned, as well as a 

 sterile form named for the purpose of convenience, the 

 " brown mealy wing fungus." This genus Aschersonia is 

 largely represented on species of Aleurodes in Ceylon. 

 RolfsJ in the same year published an account of 

 fungous disease on the San Jose scale (Aspidiotus per- 

 niciosus) and shows that it can be used to check this great 

 pest. The fungus appears to be the Microcera originally 

 discovered by Desmazieres. Two years later inoculating 

 experiments carried out in Illinois with this fungus on 

 the same insect are described by Forbes.§ He thinks, 



* Webber : U.S.A., Depart. Agric., Div. of Veff. Physiol and Pathol, 

 No. 13, 1897. 



f The genus Aleurodes does not strictly belong to the family Coccidae. 

 but to the allied one Aleurodidag. In this paper the terra " scale-insect " 

 includes members of both families. 



% Rolfs, Florida Agric. Exp. Station, Bull. 41, 1897. 



§ Forbes, Illinois do. do. 56, 1899. 



