2 University of Michigan 



capture of all of them, and the total was less than thirty indi- 

 viduals. The next day at the pond Trameas were conspicuous 

 by their absence. 



Once in Guatemala I had collected about Gualan for sev- 

 eral days with poor success. It was the very end of the dry 

 season, and the woods and fields were tinder dry. Then one 

 night it rained, a veritable downpour, for hours. And about 

 the little ponds which came into being between sunset and 

 sunrise along the railroad embankment Trameas and other 

 libellulines flew "by hundreds" in the early morning sun. And 

 yet, during the preceding days of drought I had not seen a 

 Tramea. They were really few in numbers and were scat- 

 tered far and wide through the brush and over the fields. 

 Dragonflies would be almost unknown except to a few spe- 

 cialists, if it were not for their congregating at times of 

 greater or lesser duration in habitats of very restricted area. 



Yet these habitats may be occupied for only a brief period 

 in the lives of the dragonflies. Because of their freedom of 

 flight, their relative independence of any one certain food, 

 and their limited numbers, dragonflies present in many cases 

 a difficult problem for one who would discuss their habitats 

 intelligently. To say, for example, of some species of Soma- 

 tochlora that it "frequents woodland streams," may tell about 

 as much about it as the student would learn of the activities 

 of Charles Darwin, say, if his biographer told where Mr. 

 Darwin spent his youth and gave the street address and house 

 number of his later years. For the chances are that our 

 Somatochlora from the date of its emergence till its final 

 activity (mating) may never visit the woodland stream. We 

 find it at a certain period in its life at a habitat of verv small 

 area, where it meets others of its kind. 



