2 5 8 



ENTOMOLOGY 



ent on insect-food, however, for they all possess chlorophyll. 



Bacteria cause epidemic diseases among insects, as in the 

 flacherie of the silkworm; and fungi of a few groups are spe- 

 cially adapted to develop in the bodies of living insects. 



Those who rear insects know how frequently caterpillars and 

 other larvae are destroyed by fungi that give the insects 

 a powdered appearance. These fungi, referred to the genus 

 Isaria, are in some cases known to be asexual stages of forms 

 of Cordyceps, which forms appear from the bodies of various 

 larvae, pupae and imagines as long, conspicuous, fructifying 

 sprouts (Fig. 250). 



The chief fungus parasites of insects belong to the large 

 family Entomophthoraceae, represented by the common Empusa 

 musccc (Fig. 251) ^which affects various flies. In autumn, 



FIG. 251. 



Empusa muses, the common fly-fungus. A, house fly (Musca domestica), sur- 

 rounded by fungus spores (conidia) ; B, group of conidiophores showing conidia in 

 several stages of development; C, basidium (b) bearing conidium (c) before discharge. 

 B and C after THAXTER. 



especially in warm moist weather, the common house fly may 

 often be seen in a dead or dying condition, sticking to a win- 

 dow-pane, its abdomen distended and presenting alternate black 

 and white bands, while around the fly at a little distance is a 



