PSYCHE 
VOL. XLVIII DECEMBER, 1941 No. 4 
THE FIBER TRACTS OF 
THE FUSED THORACIC GANGLIA OF 
THE ADULT EPHESTIA KUEHNIELLA ZELLER 
(LEPIDOPTERA: PYRALHUE) 
By Robert W. Pyle 
Biological Laboratories, Harvard University, 
Cambridge, Massachusetts 
The histology of the nervous system of the various orders 
of insects has been studied by many biologists, but nearly 
all of these have been concerned with the brain. As Snod- 
grass (1935) has stated the fiber tracts of the thoracic 
ganglia of an adult winged insect have not been worked out. 
Zawarzin (1924) has studied the ventral ganglia of ADschna 
larvae; his figures and descriptions are excellent. Other 
workers, Binet (1894), Graichen (1936), etc., while study- 
ing the ganglia other than the brain have failed to elaborate 
upon the fiber tracts. 
I wish to thank Prof. C. T. Brues, under whose guidance 
this work has been carried out, for helpful suggestions and 
criticisms, and Prof. F. M. Carpenter for reading the manu- 
script. 
Adult Ephestia were fixed in Bouin-Duboscq-Brasil, em- 
bedded in tissuemat and serial sections cut at 10 micra. The 
sections were stained by the protargol method of Bodian 
(1937). 
The fused thoracic ganglia of adult Lepidoptera in general 
are composed of the second and third thoracic and the first 
