60 THE ORIGIN OF INSECT TRANSFORMATIONS. 



Stored without undergoing putrefaction. This storage of honey 

 has caused further degeneration, which has cost the larva of the 

 bee its legs ; these, being no longer required to enable it to reach 

 its food, have disappeared. 



Ants form a remarkable exception among the hymenoptera in 

 the matter of gathering honey, but even they show the same pro- 

 pensity for sweet juices in a slightly different form, in their habit of 

 keeping aphides as cows from which they suck the honeydew. 



The suddenness of the change from larva to pupa and from 

 pupa to imago is probably caused by the hard integument of many 

 insects, which does not admit of gradual changes taking place. A 

 sudden change has thus taken place at the time of moulting, and 

 with the gradual divergence between the larval and imago states 

 this change has become more marked, and has necessitated the 

 intervention of a quiescent pupal stage. A notable exception 

 occurs in Melee, which in its first stage is active, and subsequently 

 becomes more like a maggot. 



To sum up, then, the separation of the functions of nutrition 

 and locomotion has caused insects to become more highly deve- 

 loped in their final stage and to degenerate in their early stage. 

 The hardness of their integument has necessitated the transforma- 

 tions taking place at the times of moulting, and the difference 

 between the larva and imago has at last become so marked that 

 the intervention of a quiescent pupal stage has become the only 

 possible means of bridging over the gap. 



Growth of Trees. — The following interesting results of expe- 

 riments relating to the growth of trees at various times of the day 

 have been sent to us by Mr. E. H. Thompson, the Government 

 Entomologist of Tasmania. Measurements were taken as far as 

 possible every three hours, with the following results :^ — From 6a.m. 

 to 9 a.m., 8f per cent, of growth; from 9 a.m. to noon, \\ per 

 cent, of growth; from noon to 3 p.m., no growth; from 3 p.m. 

 to 6 p.m., no growth ; from 6 p.m. to 9 p.m., i^ per cent, of growth ; 

 from 9 p.m. to 12 p.m., 3^ per cent, of growth ; from 12 p.m. to 

 6 a.m., 85 per cent, of growth. The greatest growths in twenty-four 

 hours were : — Banksia Rose, 6^ in. ; Geranium, 5f in. ; Wattle, 

 4^ in. ; Apple, 2\ in. ; and Pear, i^ in. — Public Opinion. 



