REACTIONS OF THE MASON WASP TO LIGHT 359 



DISCUSSION OF THE EXPERIMENTS AND CONCLUSIONS 



The experiments which supplied the data for this paper ex- 

 tended over a period of three weeks; and each day, except Sun- 

 days, from two to four sets of experiments were performed. 

 Naturally there were many repetitions of experiments and 

 responses, and many slight modifications of each. These numer- 

 ous experiments were necessary to secure the data for an im- 

 partial analysis of the behavior. To record the details of all 

 of the experiments would be an unfruitful tax upon the patience 

 of the reader; hence only a few sample experiments have been 

 recorded in the section above. The following discussion, how- 

 ever, is based upon all of the experiments that were performed. 



Feeding Instincts. Evidently Trypoxylon albotarsus is able 

 to instinctively 3 feed or drink from liquids without getting 

 into them. This is evidenced by the manner in which the wasps 

 responded to honey placed in Minot watch-glasses. Almost 

 invariably, whether it was a first visit or a subsequent one, 

 the wasp mounted or alighted on the rim of the watch-glass, 

 fed upon the honey, backed out, made a short flight of orien- 

 tation, and then flew away. Sometimes the wasp would rest 

 one of its fore feet upon the honey; but more often it would not. 

 Occasionally the flight of orientation was omitted. Only once 

 was a wasp noticed to get smeared with honey. On that occa- 

 sion the wasp waded through the honey and escaped on the 

 opposite side. After wandering about, partly on foot and partly 

 on the wing, it returned to the honey, and when it had supped, 

 backed away without getting into it. 



These wasps also displayed an instinctive tendency to drink 

 water under a variety of conditions. They were noticed to 

 drink from a watch-glass partly filled with mud, from the out- 

 side of that watch-glass, and from the cloth syphon that sup- 

 plied the watch-glass with water. One was noticed to enter 

 the bent-neck bottle, drink and back out. The sipping of the 

 honey and the drinking of the water occurred both in the bright 

 light and in the shadow. 



Responses to Brightness. In this species brightness usually 

 serves as a stimulus to activity and darkness or a dim light as 

 a stimulus to inactivity. As a rule, under the influence of a 

 strong white light, these wasps would make active flights or 



* In this article instinct is used to signify inborn responses. 



