Entomogenous Fungi. 421 



time a coccid was torn apart and examined. It was seen to be full 

 of hyphal bodies like those first found, but somewhat swollen and 

 producing nearly straight germ tubes (Fig. 3). A little later coccids 

 were found having a white fringe around them, and bearing on the 

 back small white projections like the beginnings of sphorophores, 

 composed of many threads growing together and producing a solid 

 mass. This is the beginning of the Isaria-stage. On examining the 

 fringe a condition of affairs similar to that found in the cultures was 

 observed, the flask-shaped sterigmata and conidia exactly resembling 

 those seen in the cultures. On keeping these coccids in a moist 

 chamber for a few days a dense white, cottony growth similar to 

 that produced in the cultures appeared, covering the scale. Some- 

 what later a reddish powder was seen borne directly on the coccid. 

 This proved to be made of bodies similar to the hyphal bodies (Figs. 

 1 and 4). I was unable to observe the manner in which they were 

 borne, and have been unable to produce this stage since. The short 

 sporophores mentioned as the beginning of the Isaria-stage continued 

 to grow, and on examination were seen to be made up, at first, of 

 loose fibres which unite to form a slender white sporophore bearing 

 sterigmata and conidia resembling those in the fringe and in the cul- 

 tures. Fig. 98 shows a number of coccids at this stage.* 



The cultures on sterilized scales afterward produced sporophores 

 of the true Isaria type, about 3 mm. in length and ^ mm. in diameter. 

 They reseiubled in every way the sporophores found on scales 

 growing under natural conditions. After nearly 7 months trans- 

 fers were made from these cultures to sticks of potato and pui-e 

 cultures obtained. When growing under natural conditions, the 

 apex of the Isaria-sporophores becomes enlarged and assumes the 

 form of a conical head, beai'ing closely packed rounded perithecial 

 which contain many asci about 120 microns in length and 13 in 

 diameter. They are fusiform and taper to a slender base. At the 

 apex the spores do not entirely fill out the ascus, leaving the appear- 



* 



Isaria-stage. — The sporophores are simple, slender, terete or cylindiical, aud 

 M'hite ; they are borue in groups of from 2 to 10 on tlie dorsal surface of scale- 

 insects belonging to the genus Lecanium. The sporophores arc 1 to 2 mm. long, 

 formed by the interlacing threads of mycelium and bearing sub-ovate conidia 

 2^ to 4 microns in size, on simple or once branched flask -shaped sterigmati*, 

 which are placed at right angles to the thread. The scale-insect on which those 

 sporophores are borne is often surrounded by a simple fringe of mycelium (Fig. 

 98), which also bears conidia. The apices of these Isaria-sporophores become 

 enlarged into the ascophcres of the perfect stage. 



