SUMMARY AND CONCLUSIONS. 



The present paper comprises more or less detailed observations 

 on some 28 species of Texas Solitary Wasps. It was not written 

 for the purpose of entering the discussion of mooted questions of 

 instinct and intelligence, but rather of describing clearly and ac- 

 curately the actions of some of these delightful little workers in 

 their natural haunts. 



My experiments on the mental faculties of wasps have been few 

 and therefore of little value. The experiment recorded above on 

 the sense of direction I have considered of sufficient value to be put 

 clown. It certainly has to commend it an absence of artificiality 

 liaviug been made by merely varying the natural conditions to which 

 the wasp was already accustomed. In general my observations lead 

 me to accord with the opinion held by the Peckhams and others that 

 wasps are guided by sight in finding their way— by sight and the 

 memory of familiar landmarks in the neighborhood. 



Of the varibility of instincts within a given species there can in 

 my opinion be no doubt. The variability in mental traits and dis- 

 positions as reflected in the wasp's actions, seems moreover to be pro- 

 portionate to the physicial variability. At any rate, Bemhex bel- 

 fraegi, the species of Bembidula and Microhemhex monodonta for 

 example are all very variable species in size and coloration as well 

 as in the demeanor of different individuals. 



All the species of solitary wasps either dig holes in the ground 

 for their nests or work with mud in their architectural pursuits. In 

 the case of Agenia (Chap. VI) both kinds of nests are found in the 

 same genus, some species digging typical nests in the ground while 

 others build mud cells in protected places. This fact alone, it seems 

 to me, would justify the setting-up of a distinct genus^ Pseudagenia, 

 as is done by some authorities. Among the wasps that dig their 

 nests we may recognize two methods of excavation : in one the wasp 

 utilizes the forelegs to scrape out the dirt loosened by the mandibles ; 

 in the other the wasp employs the mandibles both as pick and a? 

 shovel. Ammophila (Chap. II) and Priononyx (Chap. IX) repre- 

 sent the latter metliod and their nests are composed of a vertical 

 tunnel leading straight down from the surface (Fig. 8) to a pocket 

 whose long axis lies horizontal (Figs. 18 and 22.) The wasps work- 



