THE INTEREST IX INSECTS 



33- 



This is a most remarkable case and 

 points clearly toward intelligence, for 

 the Sphecid left the instinctive rut so 

 minutely travelled by her ancestors 

 and instantly adapted herself to the 

 most extrinsic circumstances imagin- 

 able. 



Equally interesting are the results of 

 two experiments upon different species 

 of the same group of insects which 

 were recently observed at close range 

 by the writer. These experiments are 

 well worthy of note, from the fact that 

 a vast contrast in adaptability was dis- 

 covered between two insect species, so 

 entirely identical in their anatomical 

 structure and so closely related in 

 their classification that they should 

 have been equal to each other, even 

 under the unusual circumstances in 

 which they were placed. Yet in one 

 of these experiments it was shown that 

 a certain species possessed the power 

 of instantly distinguishing between 

 right and wrong, while in the other, the 

 second species, belonging to the same 

 family, made plain its inability to 

 leave the beaten path of innate propen- 

 sity. 



As I have said, the insects in ques- 

 tion were both species of wasps ; one 

 the paper wasp and the other the com- 

 mon blue mud-dauber. Although they 

 are alike in structure and function, 

 their habits are quite at variance, as 

 we shall presently see. 



The paper wasps are a social species ; 

 that is, they live in a colony, with a 

 common den, which, in this case con- 

 sists of a group of paper tubes or cells, 

 suspended by a central stem from the 

 under sides of overhanging stones or 

 more often from old beams and tim- 

 bers in barns or sheds. The paper for 

 the nest is manufactured by the wasps 

 from wood pulp which is scraped from 

 unpainted lumber and then mixed with 

 a glutinous substance which the in- 

 sects possess. A large nest will con- 

 tain in the neighborhood of five hun- 

 dred cells, but the great majority are 

 complete when one hundred have been 

 constructed. In each of these cells 

 an egg is laid by the queen, and the 

 young are fed by the other members of 

 the colony until their period of help- 



lessness is at an end. Their food con- 

 sists of chewed up worms, spiders and 

 other insects, mixed with a certain 

 amount of nectar, and is undoubtedly 

 quite nourishing and delicious. Thus 

 it will be seen that the paper wasps 

 are of a domestic turn of mind and 

 quite different in habits from their 

 mud-daubing cousin, who is a restless, 

 nervous creature of a solitary nature. 

 This insect constructs from five to 

 fifteen cells of rich grey mud which, 

 upon hardening becomes quite sub- 

 stantial. The nest is placed in situa- 



A NORMAL NEST OF THE MUD-DAUBER WITH 

 CELLS OPENED TO SHOW CONTENTS. 



The top one contains the young of the wasp, the cen- 

 ter one the spiders with which it is pro- 

 visioned, and the bottom cell is one from 

 which the insect has issued. 



tions similar to those which the paper 

 making species select. Like the 

 Sphecid wasp, the mud-dauber fills 

 each cell with paralyzed insects, which, 

 in this case consist of small spiders. 

 Then after laying a single egg in each, 

 she seals up the opening with mud and 

 leaves the young wasps to shift for 

 themselves. 



For the first experiment, a mud-dau- 

 ber's nest was selected which was dis- 

 covered under the overhanging roof 

 of an old wood shed. The affair con- 

 sisted of ten cells, all but one of which 

 had been sealed by the wasp, who, by 

 the way, quickly appeared upon the 

 scene, carrying two small, reddish 

 spiders and fully prepared to avenge 

 all public wrongs. The burdened in- 

 sect flew directly to the nest and after 

 earefullv inspecting her cargo, to make 



