INTRODUCTION 
15 
accuracy for all ordinary purposes—and measures up to 
10 cm. 
In seeking expert help in identification care must be taken 
to state very clearly in the case of supposed fungus galls 
what information is desired. To my knowledge a cecidolo- 
gist sent a cankerous outgrowth from a branch to a well- 
known mycologist asking him to identify the fungus. He 
examined the specimen, found a saprophyte on the bark, and 
sent back its name. The collector, knowing nothing about 
fungi, jumped to the erroneous conclusion that the sapro¬ 
phyte was the cause of the gall growth. 
The shape, size, and position of the gall are secondary 
characters in diagnosis. The occupants must be examined 
carefully in all cases with a microscope or powerful pocket- 
lens, for it sometimes happens that galls of similar appear¬ 
ance caused by totally different creatures occur on the same 
species of plant. Many egregious blunders have been made 
(and unfortunately published) by cecidologists who have 
omitted to observe this elementary precaution— e.g., galls 
caused by eelworms have been ascribed to the presence of 
dipterous larvae. 
The collector’s field outfit should consist of a good-sized 
vasculum (16x8x4^ inches is as handy as any), a strong 
pocket-knife, a stout pruning-knife, a hand-saw with adjust¬ 
able blade, a few small tin boxes, and a good pocket-lens. 
Fig. 1.—Seed Pods of Lotus comiculatus , swollen and deformed 
through the presence of the Larvae of Contarinia loti. (1/1.) 
