[5] COLLECTING DRAGON AND MAY FLIES NEEDHAM. 



3 to 4 feet long^ with a double liook at oue side and a brush at the 

 other side at its distal end. To illustrate the use of this apparatus, 

 suppose we wish to collect the insects from the stones obstructing a 

 brook. We place the net directly below the obstruction and in the cur- 

 rent, and adjust it to the bottom by downward pressure on the handle 

 with one hand, while with the other we rapidly overturn the stones 

 and with the brush sweep free the clinging insects. These are driven 

 by the current into the net, which is then lifted and emptied. 



Most stone flies and many may flies and at least one dragon fly 

 (Argia putrida) are found in such situations. 



4. Transjjorting live nymphs. — In order to carry home a day's catch 

 alive, a lar-ge quantity of water is not necessary. It is well to have a 

 pail and to place w^ithin it a few smaller receptacles containing a little 

 water and to pack wet waterweed between these. Then the smaller 

 nymphs taken may be distributed among the receptacles so as to dimin- 

 ish the chances of their eating one another, and all the larger and stouter 

 nymphs may be stowed away in the waterweed, which does not need 

 to be submerged unless left long uncovered in the sun. Well-grown 

 nymphs can breathe air directly, and entangled among the stems will 

 be kept out of mischief. The canibalistic habits of certain species of 

 the larger dragon flies [Anax, etc.), and the predatory habits of all of 

 them need to be borne in mind while arranging receptacles for them, 

 and specimens differing greatly in size should not be put together. 



Great care is necessary, however, with some species, especially species 

 of stone flies, which live in rapids where the water is well aerated. If 

 these are to be transported, they must be kept in clean water and hur- 

 ried home and into suitable permanent quarters. 



COLLECTING AT TRANSFOEMATION. 



The easiest method of collecting life-history material is, doubtless, to 

 pick specimens up when transforming. To be sure, this does not give 

 the complete life history; but, since the cast skin preserves the form of 

 the nymph, and the several nymph al stages are much alike except in 

 size and length of wing cases, it gives the better part. To the general 

 collector with but little time to give to these "unimportant" groups 

 this method should appeal strongly, for by it he may, without appa- 

 ratus, and with a minimum of time and trouble, obtain most valuable 

 material. One may often find nymphs crawling from the water, imagoes 

 emerging from their old nymph skins, others drying their wings, and 

 others ready to fly, and all in large numbers, needing only to be 

 picked up. 



The value of this material maybe wholly lost, however, unless atten- 

 tion be given to three points : 



1. The maturing of the imagoes. 



2. The preservation of the often delicate exuviae. 



3. The keeping of the imago and its skin together. 



