140 



ROLAND THAXTER ON THE 



principal points of entrance. Infection, resulting from the ingestion of spores with the 

 food, does not, I think, occur as is indicated by experiments with wood crickets which 

 will be mentioned under E. Grylli; and, as a rule, the digestive tract during life does 

 not seem to be penetrated by the fungus. 



After the hypha of germination has entered the body of the host, it develops with some 

 rapidity at the expense of the softer tissues. This growth usually differs from that de- 

 scribed in Conidiobolus from the fact that, instead of producing a branched mycelium, 

 the hyphae multiply, not by branching and continuous growth, but by the formation of 

 what I have previously called hyphal bodies, which consist of short, thick fragments, of 

 very varied size and shape, that are continually reproduced by budding or division until 

 the insect is more or less completely filled with them. In some instances these hyphal 

 bodies have been observed as naked masses of protoplasm with an amoeboid movement, 

 as is stated to be the case in E. colorata; but in most instances a cell wall may be dem- 

 onstrated. In E. Grylli, at an early stage, the hyphal bodies may be seen loosely adher- 

 ing in clusters as a result of continued budding; but more often in this and other species 

 they occur singly or in pairs. It is probable, however, that this mode of development is 

 subject to considerable variation and that in some instances a mycelium maybe produced 

 directly, after the entrance of the germinating hypha. I have been unsuccessful in en- 

 deavoring to cultivate conidia in sterilized solutions; although, by employing a drop of 

 Avater in which numerous aphides had been crushed, I was enabled to obtain a fairly 

 vigorous growth from the conidia of E. aphklis. In this case the germinating hypha 

 branched in all directions, forming a considerable mycelium with numerous septa; but, 

 owing to the lack of nutriment as well as to the presence of bacteria, the hyphae soon 

 became much attenuated and finally died. DeBary 1 states that this production of a 

 mycelium as a first result of infection occurs in E. ovispora, E. curvispora and E. 

 sjjhaerosjjerma (radicans) ; but, according to Nowakowski, in his summary of the Em- 

 pusae* the first two are not thus characterized, while my own observations of E. sphae- 

 rosperma do not bear out his statement that the "fungus growth" within the host is 

 filamentous in all cases. It seems not improbable that both forms of development may 

 occur under different conditions; but, however this may be, the termination of the first 

 or merely vegetative condition of the fungus consists in the production of a mass of 

 hyphal bodies which fill the host more or less completely; and in no instance, I believe, 

 is this stage or its equivalent omitted by the direct growth of the original hyphae into 

 conidiophores. On this assumption, in cases where a direct mycelial growth follows 

 the entrance of the hypha of germination, if indeed such instances occur, this myce- 

 lium must fall to pieces into hyphal bodies, before the commencement of growth the 

 direct object of which is reproduction, in a fashion resembling that above described at a 

 similar stage in Conidiobolus. 



The hyphal bodies, the production of which usually marks the end of any appropria- 

 tion of nourishment from the host and generally occurs at about the time when the host 

 has ceased to live, arc in many cases somewhat different from those which have previ- 

 ously characterized the fungus and often possess great regularity, both in size and 

 shape, closely resembling spores. In E. Fresenii, for example, the original hyphal bodies 



1 Vergl. Morphol. d. Pilze, etc. 



2 1, c, B, p. 17C. 



