189] LIFE HISTORY OF GOKDIUS AND PARAGORDIUS—MA 7 69 



opportunity to observe in the search for young parasitic forms in sections 

 of hosts. The tube is either nearly or entirely closed at the anterior end and 

 widely open at the posterior end. 



Since the fluid in the body cavity of the insect is itself partly excretory 

 in nature it is difficult to understand how a large parasite can live in that 

 fluid and possess no trace of an excretory system. 



Meissner already regarded the intestine as an excretory tube, but did 

 not recognize its true ontogenetic position as a part of the alimentary 

 canal. Montgomery regarded the bodies enclosed in the intestine of the 

 larva as excretory in nature. 



Functions of the nervous system. All reactions in the two species observed 

 are of a very low nature. The most definite response observed is the grasping 

 reaction of the male when in contact with the body of the female. All 

 other responses consist merely of motion, the degree of motion depending 

 both upon the magnitude of the stimulus and the state of activity of the 

 specimen. In case of specimens at rest it usually requires several successive 

 stimuli to produce any great irritation. There is no direct response to 

 light in case of free specimens, but the difference in the activity of the 

 specimens at different times of the day may be partly due to the difference 

 in the light intensity. The most definite case of orientation to light is the 

 orientation of the developed specimens in the abdomen of the host so that 

 the anterior end is always at the point of exit. This orientation may, how- 

 ever, be in part due to some other agent. The emerging reaction on contact 

 with water is next to the grasping reaction of the male the most definite 

 response to stimuli, but the reaction here is also nothing more than motion. 



