gS THE SENSES OF ANIMALS 



Other tests can be made with some of the day-flying moths 

 which mate with the aid of scent particles Kberated by the 

 females in order to bring the males to them. 



Moths, such as the Emperor and Oak Eggar, are very 

 suitable for this. April to mid-May is the period for tests 

 with the Emperor Moth ; and July to mid-August for the 

 Oak Eggar. When the females first emerge from the pupa 

 they give off scent from glands near the vent, and this scent 

 is carried by the breeze over quite a wide area. In nature 

 males will very shortly come up wind and find the resting 

 females. Pairing results, after which the females cease to give 

 off scent. 



A very interesting and dramatic experiment can be carried 

 out with a captive female. One which is known to be newly 

 emerged should be placed in a box with a muslin top, or 

 in a container made from perforated zinc. If the receptacle 

 is placed out of doors, it will not be long before a male or 

 males will arrive. These will settle on the box containing the 

 female. Once this has happened, the male may be allowed 

 access to the female by opening the box ; mating will occur 

 and later the female will lay eggs which, if the student so 

 desires, can be kept with the object of rearing the caterpillars 

 in due course. 



To prove beyond doubt that scent is the reason for the 

 males locating their mates a further experiment may be 

 performed. To do this, leave the female in her box for, say, 

 an hour; after this take her out and put her in a cage well 

 away from the spot where the box was situated. The males 

 will arrive and make straight for the box and show every 

 sign of interest in it; I have carried out both these tests in 

 my own garden which is situated not less than a mile from 

 the nearest area known to have a population of the moths 

 in question. This particular kind of behaviour is known 

 among entomologists as "assembling" — a very apt word. 



Ants are very sensitive to odours and they, too, can locate 

 a source of food some distance from their nests. An ingenious 

 student can easily devise tests to demonstrate this. 



The so-called burying beetles are, perhaps, the most re- 

 markable insects in respect of their scenting powers. These 

 beetles seek out the dead bodies of animals — mice, toads, 



