idly, and have been known to produce images before the close 

 of the same season. Trnmerf also seems to be two-brooded, 

 emerging numerously both in spring and fall. On the other 

 hand, the nymphs of the Gotuphidw probably require more 

 than a year in which to mature, emerging in the second or 

 third season after hatching. The one-year life cycle is, how- 

 ever, the rule among the LibeUiflidd', which contains most of 

 our commoner Anisopfera, the eggs laid during midsummer 

 hatching in late summer, and the nymphs maturing in time for the 

 general emergence the following season. In late August there 

 is a surprising number of very small nymphs, — tiny spider-like 

 youngsters, — and even in September and October the prepon- 

 derance of young nymphs is still manifest. As the period of 

 maximum emergence of their species approaches, usually in early 

 summer, they mostly attain full size, and are at this time most 

 readily seen &,nd captured and apparently more abundant than 

 in the fall, when they were small and easily overlooked. With 

 regard to the Zi/gopfera, it is highly probable that there are a 

 number of broods in a season, the processes of transformation and 

 oviposition beginning as soon as the weather permits and con- 

 tinuing industriously to the close of the season. 



In the species whose life cycle is apparently more than a 

 year the nymphs are of two or three distinct sizes, the largest 

 presumably being of the next brood to emerge. In species 

 whose life cycle is completed within a year, the nymphs are 

 fairly uniform in size, but there is, nevertheless, a sufficient 

 extent of variation to cause a considerable number of strag- 

 gling emergences during the season ; and it therefore follows 

 that, in general, nymphs of nearly all species of Odonafa may 

 be found throughout the entire season. Because of this fact it 

 has not seemed worth while to give dates of the occurrence of 

 nymphs. The accessible data concerning the imago period, on 

 the other hand, is very fully given, thus indicating the limits 

 of the nymphal period also. 



Like many other imniature aquatic forms, the groundcolor 

 of the nymphs darkens greatly up to the close of each molting 



