142 



ROLAND THAXTER ON THE 



branch indefinitely, each ultimate branch becoming a conidiophore similar to those of the 

 more simple case just mentioned. This usually occurs where the conditions of growth 

 have been very favorable and may be found side by side with the more simple form. 



Although the number of germinating hyphae developed from a single hyphal body is 

 usually small, not as a rule exceeding one or two, certain instances occur in which the 

 number is considerable. In E. conglomerata, for example, as described by Sorokin, long 

 hyphal bodies are found which germinate in all directions and are not unlike, in this re- 

 spect, the hyphal bodies previously mentioned in Conidiobolus. These hyphae subse- 

 quently branch and anastomose, forming a coherent mass which Sorokin has termed a 

 stroma, and on which he has based a classification of Empusae into " Stromaticae " and 

 " Astromaticae." It is probable, however, that this condition is interchangeable with the 

 more ordinary form, since in some specimens for instance of E. apiculatus, I have found 

 well marked stromata, while in others the direct development of the conidiophores from 

 hyphal bodies has been distinctly traceable. 



The most singular modification of this kind, however, occurs in E. aphidis and virescens 

 which are the only species thus far in which it has come under my observation. Here 

 we have a body which appears to be of the same nature as the hyphal bodies in other 

 species, of regular spherical form and with a highly refractive fatty contents, from which, 

 soon after the death of the host, hyphae begin to germinate in all directions and in in- 

 credible numbers, in a fashion that reminds one of a head of Aspergillus (figs. 239 and 

 261). The hyphae thus produced then branch and divide, becoming separated into a 

 mass of irregular, short, contorted hyphae which fill the host and distend its body. This 

 breaking to pieces of hyphae produced from hyphal bodies also is found in species where 

 the usual type of germination occurs: as in E. muscae, in which, just before the emer- 

 gence of the conidiophores, the body cavity contains a mass of irregular short hyphae 

 together with germinating hyphal bodies. 



Formation of conidiophores. — The germination of the hyphal bodies results either in 

 the production of sexual or asexual resting spores (zygo- or azygospores) ; or of coni- 

 diophores bearing conidia. In the latter instance hyphae, arising directly or indirectly 

 from the hyphal bodies, grow rapidly outwards, burst through the less resistent por- 

 tions of the host's integument in spongy masses, in most instances of a livid white color. 

 These masses sometimes vary to pale or bright green or dull olive, even in forms where 

 their normal color is white ; and there is considerable variation in their general appear- 

 ance according to the species or to the conditions of their development. In some cases, 

 they barely project beyond the body of the host and are confined to the points of emer- 

 gence which are generally afforded by the thin intersegmental membranes through which 

 they project in cushion-like rings as in E. muscae. In other cases, the external growth 

 may be more extended and the masses may coalesce so as to cover the whole body with 

 a continuous layer of conidiophores which may form a mass several times as large as 

 the insect from which it springs. 



In the first and more simple case, where there is little external fungus growth, the 

 cushion-like masses are usually formed by simple conidiophores (fig. 1) which, although 

 each may be derived in common with many others from the same hyphal body, are yet 

 ultimately simple, producing few or no branches outside the host's body and giving rise 



