THE INSECT WORLD 



substance was being produced in the head; when enough had 

 been accumulated in the blood, the insect could moult even 

 if the head was removed. This interpretation was confirmed 

 by decapitating two bugs, one which had moulted less than 

 five days previously and one which had passed this critical 

 period. The two headless insects were connected by a fine 

 glass capillary tube and it was then found that they both 

 moulted at the same time. This control of form and structure, 



Fig. 3 

 Two 4th instar nymphs of 

 Rhodnius decapitated and con- 

 nected by a capillary tube sealed 

 into the neck with paraffin wax 

 (after Wigglesworth). 



partly nervous and partly glandular, may, it is beginning to 

 appear, have great significance in some social insects. In 

 termites especially, the body sometimes seems to be moulded 

 by the needs of the community, and the intervention of the 

 brain may make this possible. 



REPRODUCTION 



In most insect species, the mature female, after being 

 fertilized by one or more males, lays between fifty and one 

 thousand eggs; the actual number largely depends on the 

 manner of life of the species. These eggs hatch out into a 



23 



