G l-r.\V.l PARASITIC UPON ALKYRODKS CITRI. 



years. As early as 1T54, according to M. C. Cooke, 1 a popular description 

 was written by Father Torrubia of a fungus growing out from the bodies 

 of wasps. Father Torrubia had collected specimens of this at Havana, 

 Cuba, as early as 1749. Cooke thinks that this fungus was Cordyceps 

 specocephala. lie quotes Torrubia's account from Edwards' "Gleanings 

 in Xatural History," published in 1<5S, and says that this species represents 

 the rather celebrated vegetable wasp which had a romantic history a century 

 l.efore. Cooke also gives an account of a species of Isaria, which had been 

 known as early as 1782 on the Sphinx moth. 1 He mentions as many as 

 1!7 species, representing 39 genera of fungi, that have been found growing 

 upon various insects. The majority of these species are included by Cooke 

 under ."i genera: Cordyceps, with 48 species; Laboulbenia, with 34 species; 

 Isaria, with 2\ species; Entomophthora, with 22 species; and Empusa, with 

 13 species. Since then main new genera have been added to the ento- 

 inngencms fungi. Species of Cordyceps found on wasps, bees, ants, cater- 

 pillars, and scale insects, have been mentioned by many scientists and 

 popular writers from the last-mentioned date down to the present time. 

 Cooke refers to the "History of Insects" by Murray, published in 1838. as 

 containing interesting accounts of fungi growing upon insects. 



The Tulasne brothers were probably among the first to study the para- 

 sitism of these fungi. They published descriptions of some of them in 

 L857, a and of others in isii.").-' Among those described in 1865 was Sphaer- 

 ostilbc cticcophila Tul.. which is one of the species treated of in this thesis 

 as sometimes parasitic on Alcyrodcs citri. The work of Pasteur on the 

 flacherie of the silkworm, marked a great advance in our knowledge of 

 insect diseases. This disease was due to a species of bacterium. Pasteur's 

 work was taken up with the view of protecting the insect from parasitic 

 growth, while most subsequent work has been carried on with the view of 

 destroying insect pests by means of their parasites. A work of much scien- 

 tific importance was that of Roland Thaxtcr, :: "The Entomophthoraceae of 

 the I'nited States", published in 1888. The genera which he studied attack 

 flies, beetles, moths, caterpillars, grasshoppers, and plant lice. 



Since the institution of Experiment Stations in the United States, ex- 

 periments have been made with several species of fungi, with a view of 

 using them in combating insect pests. l"p to this time the greatest degree 

 of Miccess has l;een attained in Florida, where the conditions of temperature 

 and moisture are conducive io the spread of fungi. The use of fungi to 

 combat insect peMs has met with only limited success in the Northern States. 

 A number <>f years agn the employment of a species of Sporotrichum for 

 spreading disease among chinch-bugs received much attention. Tn 1895. 



'Vegetable Wa>p> and Plant Worm-. pp. U-48, London. ls.:.. 



2 Cookr. M. C' \Ym-ialili- Waspv and IMant Worms. ,,],. ;,, :;;; n 73 <,<; j |- ]s -. , n( > 



881. 

 'Mi-moil-* of tin- P,.,MOH Soi-irtv of Natural History. Vol. IV. Xo. 6. 



