ENTOMOPHTHOREAE OF THE UNITED STATES. 145 



which branch and elongate, growmg constantly more attenuated, their protoplasmic con- 

 tents becoming separated by successive cross partitions from the empty hyphae left behind 

 (flg. 240) . It may here be mentioned that this separation by cross partitions is common 

 in the general growth of the fungus. The hyphae produced thus from conidia have the 

 usual characteristics : a granular protoplasmic contents which often shows a very notice- 

 able streaming motion, and contains large oil globules and a hyaline wall. The power 

 of gerniination lasts, according to Brefeld, at most only a week, or slightly more in 

 E. radicans {^E. spliaerospermd) ; but in my own experience I have found the period 

 usually much shorter than this. The period is in all j^robability very variable ; spores 

 that have been formed under unfavorable conditions being better able to withstand simi- 

 lar conditions : the endurance of the spores, moreover, varies with different species. As a 

 rule, germination takes place very soon after discharge, and if the conidium has neither 

 fallen upon a proper host nor upon a wet surface it proceeds to form 



Secondary conidia. — The secondary conidium is a provision for further dissemination 

 in case the primary spore has fallen on a substance unsuited to its proper development. 

 The most common method of formation consists in the production of a hypha of vari- 

 able length, which, growing verticallj^ upwards, becomes swollen at its extremity into a 

 basidium, and produces a conidium similar to that whence it is derived. This is dis- 

 charged in the usual fashion, and may in turn produce tertiary, etc., conidia, in a similar 

 way, until its vitality is exhausted or it has found a suitable lodgment. The conidio- 

 phore formed in this process is usually simple, even if the type from which it was de- 

 rived is digitate ; yet I have seen, in a case where numerous spores had been discharged 

 upon wet moss, that the hyphae arising from them united to form a mass of conidio- 

 phores of the digitate type peculiar to the species. 



Although the form of secondary conidium just described is most commonly found, 

 and is apparently the normal type in all species under favorable conditions, it is subject 

 to several interesting variations that are dependent, for the most part, upon an insufficient 

 supply of moisture. The first of these consists in the production of a secondary conid- 

 ium quite different from the primary, either by direct budding from it (fig. 9) , or borne 

 upon a short hypha of germination (fig. 362). These conidia are also discharged; but 

 are aj^parently better suited to resist unfavorable conditions than the ordinary ones, and 

 probably retain their power of germination much longer. The most singular modifica- 

 tion, however, is presented by a few species allied to^. spJmerosperma and E. Fresenii. 

 In these forms and their allies, when the conditions of moisture are unfavorable for the 

 ordinary process, a long, slender, capillary conidiophore is produced, on the end of which 

 is borne a peculiar secondary conidium differing still more widely from the parent spore 

 than in the case just mentioned. 



These secondary conidia (figs. 157, 191, etc.) are, with one exception, nearly almond- 

 shaped, with noticeably thick walls, and are not discharged. "Whether they ever produce 

 tertiary spores similar to the primary ones, I have been unable to determine; but the for- 

 mation from them of tertiary conidia suuilar to themselves is not uncommon. They may 

 often be seen germinating by means of an irregular hypha which, beginning as a drop- 

 like protuberance from the apex of the spore (fig. 119), may grow to a considerable 

 length (fig. 122). Eidam, in his paper on Basidiobolus (PL 9, fig. 16), figures a mode 



