7° 



Minnesota Plant Diseases. 



and model has been formed ; this mummy contains a great 

 abundance of food material, but no part of the insect can be 

 found in it. The mummy now acts as a storage and resting 

 organ and requires apparently considerable time — months, 

 perhaps — to ripen. Under favorable conditions this mummy 

 will send up an orange-colored club-shaped body, which will 

 again produce the kind of spore which was described at the be- 



Fic. 31. — Various kinds of caterpillar fungi with fruiting bodies. (Cordyceps militaris, C. 

 stylophora and Isaria sp.) The forms of the caterpillars are preserved by the fungus 

 storage organs and the upright clubs bear the spores. 1 and 2 bear clusters of pinched- 

 off accessory spores; 3 and 4 bear sac- spores in capsules. (See chapter 9.) About 

 natural size. Original. 



ginning of this account. Under some conditions, however, the 

 mummy can be made to produce a dense growth of threads 

 from its entire surface, so that it looks like a small ball of cotton, 

 and from these threads another kind of spore is formed. These 

 spores are pinched off in great numbers. They have the power 

 of germination and infection of the larva in a way similar to 

 that of the sac spore already described. Caterpillar fungus 

 epidemics are not infrequent and thousands of larva may be 



