ASCOSPORE EXPULSION OF ENDOTHIA PARASITICA 431 
expulsion was recorded equally well by slides in either position. 
Form A was designed to prevent excessive washing of the slide by 
the rain, while form B allowed a more ready penetration of the water. 
This device has been designated as an "ascospore trap" to distinguish 
it from other kinds of spore-traps (5, 8). 
The original plan called for the placing of sets of ascospore traps 
on typical lesions under three different field conditions: first, in young 
chestnut coppice; second, in a chestnut orchard; third, in a forest. 
Owing to lack of assistance it was necessary to omit the traps from 
forest trees. A suitable chestnut coppice was found near West 
Chester, Pa., and the orchard of the Paragon Fruit and Nut Co.,, 
Martic Forge, Pa., was selected for the second set of traps. A set of 
standard weather instruments, including a rain gauge, Friez thermo- 
graph, and Friez hygrograph was installed at each station. Following 
each rain or rain period the slides were collected and brought to the 
laboratory and a record made of the amount of ascospore expulsion, 
shown for each trap. 
The Traps at West Chester 
A total of 76 ascospore traps were set on trees 4 to 8 inches in 
diameter, in a badly diseased coppice growth of native chestnut. 
Trees were selected so as to give varying conditions of the lesions, 
with perithecia in different stages of development. Some of the 
pustules showed perithecia which were just reaching maturity when 
the traps were set while others judging from the conditions of the 
pustules had probably expelled spores during the previous summer. 
The first traps (1-16) were set on November 26, 1912; a second lot 
(17-32) were placed December 3, 1912; another addition (33-36) was 
made December 18, 1912; and the number was further increased 
(37-49) on December 31, 1912. Nos. 1-49 inclusive were under con- 
tinuous observation during all or part of the winter of 1912-13. 
During the spring several more traps (50-52) were set. A fence made 
of chestnut rails gave an opportunity to test ascospore expulsion under 
different conditions, and on May i, 191 3, traps (53-56) were placed 
over areas of perithecial pustules on several rails. The last traps 
(57-76) were set August 15, 1913. Nos. 50-76 included no perithecia 
that had reached maturity and expelled spores during the previous 
season (1912). 
