16 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 
In the conidiophore stage on the tree the fungus hyphe break forth 
in groups from between the body segments and extend out as long 
slender threads, which in turn branch and form numerous fruiting 
organs. This stage of the fungus has been taken only from adult 
thrips on the tree and not from the larve, and it has been found 
present almost everywhere that the pear thrips has been collected. 
There is no doubt that the fungus spends a part of its life on the tree 
and a part in the ground, the rapidly fruiting stage among the active 
thrips and the heavy-walled dormant stage within the hibernating 
individuals in the ground; but we can only surmise how it is carried 
from one to the other. The bodies of the larval thrips within the 
eround are all absorbed by the fungus and naturally, therefore, the 
spores must be carried to a new host before they can germinate to 
any great extent. We have found adult thrips in the ground whose 
dead bodies contained only a few spores and others which developed 
some of the external mycelial growth within their cells. If this were 
often the case, and these individuals in the ground produced fruiting 
spores as they do on the trees, it would be an easy matter for healthy 
individuals in coming from the ground to become accidentally infested 
and to carry the parasite up to the tree where, because of the gre- 
garious habits of the insect, it would spread rapidly. 
The fungus grows readily in the nutrient agar under ordinary con- 
ditions and seems to retain its virulence and can be transferred from 
cultures to the living thrips. The fungus may prove to be a check 
for the pear thrips, but its effectiveness is uncertain because it is so 
subject to climatic conditions. 
Wier s) >on Pres — 
