2 HENRY H. P. SEVERIN AND HARRY C. SEVERIN 



those of naturally dead specimens. A glance at figures i and 2, 

 Plate I, p. 47, of the death-feigning postures of Belostoma when 

 compared with figures 4 and 5 of those naturally dead shows a 

 marked difference in the position of the limbs. In the dead 

 specimens as w^ell as in individuals which are dying, the abdo- 

 men often droops considerably as shown in figure 6. In Nepa 

 it becomes at times impossible to distinguish with the eye alone, 

 a death-feigning specimen from one that is really dead. As a 

 test, a number of dead Nepas were placed in a dish containing 

 feigning specimens and an entomologist, who was familiar with 

 the habits of these insects, was asked to separate the dead from 

 those feigning. This experiment was repeated several times, but 

 in each case several mistakes were made in separating the speci- 

 mens into the two classes. 



2. How to elicit the death feint: To bring about the death 

 feint in Belostoma is usually a very simple affair. The creature 

 often assumes this immovable condition when raked or scooped 

 out of the water. When picked out of the water from an aqua- 

 rium it often becomes motionless. Sometimes, however, the 

 insect will not feign w^hen taken out of the water, but will kick 

 about vigorously in an endeavor to free itself. Such a specimen 

 may usually be put into the death feint by a method which we 

 employed throughout most of our experiments. The individual 

 was held by the lateral margin of the thorax, ventral surface 

 upward, between the thumb and forefinger of the left hand 

 and then the thumb of the right hand was repeatedly placed in 

 contact with the abdomen immediately behind the last pair of 

 legs, while the fore-finger of the same hand was placed in contact 

 with the wings. Immediately the insect passed into the death 

 feint and the limbs alw^ays assumed a very characteristic posi- 

 tion (fig. 2). 



To cause Nepa to feign death, either in the water or out of it, 

 is not a difficult task. When the bug is in the water, a light 

 touch W'ith a pencil or other object upon the back will usually 

 throw it into the death feint. The same effect may often be 

 produced by taking the hemipteron out of the water with a 

 pair of forceps, grasping it by the body, breathing tube or any 

 of the legs. If this method fails, the death feint may usually 

 be elicited by dropping the insect upon a table from a small 

 height. Even w^hile feeding, Nepa may be put into the death 



