2214 Journal of Applied Microscopy 



both resting spores and "grubs." On account of the better condition of the 

 fungus in the caterpillars, they have been used much more than the grasshoppers. 



In a few hours after the caterpillars had been placed in the Petri dishes the 

 fungus began to show between the segments of the body, conidia being thrown 

 off with considerable force in all directions. The conidia which are sticky 

 adhered to the sides and top of the dishes, giving them a frosted appearance. 

 Moisture condensed on the inside and caused the spores to germinate within a 

 comparatively few minutes. It is probable that infection occurs by the sticky 

 conidia becoming attached to an insect, although I have not actually observed 

 it. Toward evening grasshoppers climb to the tops of the plants on which they 

 have been feeding. If there were dead ones there, conidia might be developing 

 and be thrown on to the live ones. This might happen any night when the air 

 was damp. If the body of the grasshopper was slightly moist where the coni- 

 dium was attached, it would germinate at once and in all probability the hypha 

 of germination would enter the body. 



Hyphae which were protruding from the bodies of caterpillars were removed 

 and drawings 1 made from them. The hyphae were for the most part simple, 

 though there was occasionally one that was branched (Fig. 1), and divided by 

 septa into cells of different lengths. Most of the cells were empty except the 

 terminal one, which was considerably enlarged and tilled with a vacuolated mass 

 of protoplasm (Figs. 1-3, 8). The terminal cell functions as a basidium (Figs. 

 2, 3, 8). Conidia in different stages of development were attached to the basidia 

 (Figs. '\La, 3^:, 8<?). There were also basidia from which the conidia had become 

 detached (Figs. 4, 8/'), open at the top, and presenting the appearance of a slen- 

 der vase with a short neck just below the more or less ragged mouth. 



On examining the body cavities of the grasshoppers and caterpillars before 

 the hyphae had begun to show on the outside, they were found to be packed with 

 rounded, irregular-shaped bodies (hyphal bodies) (Figs. 15, 16) and empty fila- 

 ments or else hyphal bodies mixed with masses of filaments containing proto- 

 plasm and lying parallel to one another. The hyphal bodies were at times con- 

 siderably elongated and arranged in the same way. The empty filaments might 

 have been mistaken for pieces of detached hyphae from the hyphal bodies, had 

 it not been for a few in which the hyphal body appeared as if lying in the fila- 

 ment after the manner of chlamydospores. In some cases the hyphal bodies 

 were rounded (Fig. 10) and resembled spores, others were irregular in shape and 

 with one or more projections (Fig. 15). 



The hyphal bodies seem to be a partial resting stage of the fungus, for when 

 the insects were placed in the moist chamber the hyphal bodies sent out hyphae 

 which pushed through the segments of the body and finally bore conidia. None 

 of the hyphal bodies were found in the alimentary canal, but were in other parts 

 of the body, even in the grasshoppers' legs. Just what these hyphal bodies are, 

 it is difficult to say, but they appear to be the result of the breaking up of the 

 mycelium of the fungus after it has used up the greater part of the available 

 nutriment contained in the body cavity. The finding of interstitial bodies in the 



^All of the drawings have been made by means of the camera lucida and microscope, 

 No. 4 ocular and No. 3, 5 or 8 objective. 



