88 ODONATA. 



men, and several other drops followed at irregular 

 intervals. At 12.53 the dragon-fly spread its wings, 

 (up to this time they had been held closely together) : 

 after spreading they remained motionless, and were 

 not moved upward and downward. The basal and 

 middle spots in the wings (see PL III., Fig. 32) were 

 well developed, but the distal spots were confined to 

 the anterior veins ; the color at the tips came slowly. 

 At 1.5 1 the dragon-fly, without giving any warning by 

 raising and lowering its wings, in other words without 

 any prehminary exercises, flew from the netting to the 

 window, a distance of about a foot. Three hours and 

 eleven minutes had passed since the transformation 

 began. 



After a long larval and pupal existence covering a 

 period of ten or eleven months, the mature dragon- 

 flies usually live but a short time, though longer than 

 the Ephemeridae. Although the metamorphosis of 

 the insect is direct, the young and mature forms live 

 under entirely different physical conditions, one being 

 aquatic and the other aerial. They accordingly dif- 

 fer more in structure than do the larval and full-grown 

 locust, which are terrestrial, and which live in the same 

 habitat and under very similar physical conditions. 

 We shall see in the orders of insects, and in those 

 groups in which the physical surroundings, food, etc., 

 differ still more widely, as they do in many cases, 

 that greater differences arise between the larval and 

 adult stages of the same insect. 



After the Ephemeroptera and Odonata are studied, 

 it will be seen that the dragon-flies have larvae which 

 are much wider departures from the Thysanuroid form 



