200 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



continue the cycle of the parasite within the mosquito host, are only 

 present and available to the mosquito at definite intervals, and that 

 after a certain time, if no reinfection occurs, these forms disappear 

 altogether. 



In conclusion the writer wishes to point out that he is fully aware of 

 a certain class of blood-parasites and transmitters which apparently 

 do not conform to the principles above laid down. One class are the 

 diseases transmitted by ticks, where the parasites are directly trans- 

 mitted from the tick host to its offspring, and where, for this reason, 

 the insect remains a potential transmitter for a very long period. 

 Another class are the trypanosomes which apparently thrive in a 

 number of different vertebrate hosts and may be transmitted from 

 cattle or wild animals to man. But the observations on this point 

 are by no means conclusive and it is quite possible, as has been repeat- 

 edly suggested, that a number of organisms, different but indistin- 

 guishable, are involved. It may prove that a revision of the data, 

 from the present viewpoint, may materially alter our conceptions on 

 the subject. 



UTILIZATION OF FUNGOUS PARASITES OF COCCID^ AND 

 ALEURODIDJE IN FLORIDA 



By J. R. Watson, Florida Agricultural Experiment Station 



As this station is receiving a number of inquiries concerning the 

 success of the experiments which for several years have been in prog- 

 ress here looking towards the control of our worst citrus pests by 

 means of fungi, it has seemed that perhaps a brief statement on the 

 present status of the subject might not be without interest to readers 

 of the Journal of Economic Entomology. The more so as there 

 seems to be among entomologists a feeling (perhaps well founded as 

 far as most of the states are concerned) of pessimism concerning the 

 practicability of controlling any insect pest by means of its fungous 

 enemies. 



Although fungous enemies are here very efficient in checking the 

 ravages of many other insects, as for instance the larvse of many 

 lepidoptera, the most attention has been given to the scales and to 

 the whiteflies of citrus, and it is with these that the WTiter will chiefly 

 deal in this brief notice. 



History. The presence of parasitic fungi (the Red Aschersonia) 

 was first noted as checking the work of whitefly in Florida by H. J. 

 Webber in 1893 (Report of Fla. Hort. Soc, and Bull. 13 Div. of Veg. 

 Path. U. S. D. A.). Prof. P. H. Rolfs (Fla. Bull. 41, 1897) first noted 

 the Red-headed Scale Fungus (Sphoerostilbe coccophila) as being a 



