18 INTRODUCTION TO THE STUDY OF FUNGI 



Mmpusa muscae. When the spore of one of these moulds alights 

 upon the body of its favourite host-insect it sends out a germ 

 tube, which enters the body at any favourable spot, and when 

 this is once accomplished, it develops rapidly, at the expense of 

 'the tissues it replaces. It does not form a branched mycelium, 

 but grows by the production of hyphal 

 bodies (Fig. 5), which are short, thick 

 bodies of variable size and shape, and these 

 continue to multiply, by budding or gem- 

 mation, until they fill the insect. It is 



Fio. 5.— Hyphal bodies possible that in some cases a mycelium 

 ^Jr^ktkoraceae. q{ ^ ordinaiy j^ may be producecL 



When the whole interior is absorbed, 

 and of course the insect is dead, the vegetative stage ends, and 

 the reproductive begins, by the protrusion into the atmosphere 

 of conidiophores terminated by conidia, either singly or in % 

 bundles, until the body is covered with the conidia, ready to 

 be dispersed. This is the asexual reproduction of conidia, but 

 resting spores are also formed, which may be sexual or asexual, 

 according to the species. In some cases 

 the conjugation of two threads of the 

 mycelium, and in others the conjugation 

 of two of the hyphal bodies (Fig. 6), results 

 in the formation of a zygospore. There is 

 a peculiarity about the conidia which may 

 be noticed, which is, that should a ripe 

 conidium not be able to find or enter 

 a host-insect, it can proceed to germinate 

 and form a secondary conidium, which 

 has the same power of infection, and 

 may be more fortunate. If this also 

 fails, the secondary conidium may pro- 

 duce a third, so that the vigour of the 

 conidia is kept preserved until able to 

 infect a host. Possibly the Isaria moulds, in the interior of 

 insects, extend their mycelium in a similar manner by budding, 

 as they are also granular rather than filamentous. 



In opposition to the views of some mycologists of ex- 

 perience and repute, we still remain persistent in our adhesion 



Fio. 6. — Hyphal todies in 

 Entomophthoraceae con- 

 jugating. After Thaxter. 



