XIL] NEW DISEASE OF GRASS. 59 



cells gradually reach the tips of the branches they break 

 into innumerable extremely small globose spores or con- 

 idia, as shown at A, Fig. 20, enlarged 1000 diameters. 



It should be noticed here how closely these Isaria 

 spores or conidia resemble in size the Torrubia, spores at 

 J, Fig. 22, and how extremely small they are as compared 

 with the spores or conidia of the mildew of onions, Per- 

 onospora Schleideniana, Ung., illustrated to the same scale 

 at C, Fig. 15. 



Isaria fuciformis, Berk., is a remarkable fungus, for no 

 other British species of Isaria is known to grow on a 

 living plant. Some species grow on dead flowers and 

 dead twigs and stems, others on decaying fungi, one upon 

 cat's dung, and another on dead spiders. Some species of 



FIG. 21. 

 Living Wasp, with fungus growths. Twice the size of nature. 



Isaria grow upon dead hymenopterous insects, others grow 

 upon living bees and wasps. One species of Isaria grows 

 in this country on dead pupce, another on dead moths ; 

 but it is known that these creatures are attacked by the 



