DESTRUCTION OF INSECTS DT FUNGI. 



45 



concealed in them which are infested by vegetable parasites. 

 The commonest example is the mould (Empusa muscce, 



FIG. 39. Empusa muscce Cohn. A, a dead fly, surrounded by spores: B, 

 spores; C, germinating spores forming secondary spores; D. empusa cells 

 growing in the fat-body of a fly ; at E forming tubes; F, partly diagrammatic 

 representation of the fructification ; x, the skin of the fly; y, it's hairs: at o the 

 spores bearing hypha-ends boring through the skin; b, the hypha-tubes re- 

 maining in the body; c. one not yet penetrating the skin; d, spores thrown off 

 from the body, and adhering to the hairs After Brefeld, from Judeich and 

 Nitsche. 



Colm, Fig. 39), which destroys the common house-fly at 

 the beginning of autumn. 



The Destruction of Insect Pests by means of Insect Fungi. 



-When insects so multiply and abound in great numbers 



as to become overcrowded, epidemics are liable to arise and 



carry them off in great numbers. These insect plagues are 



