268 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.49. 



The eggs i)robably pass the winter in the live cambium tissue of the 

 twigs, for in a twig I kept alive until January 1, 1914, the eggs were 

 yet unhatchecl. While traveling with it the twig died, so further 

 observations were impossible. As the eggs are laid in bushes which 

 in the floods of spring snow water would be partially submerged, the 

 hatching nymphs probably find their way easily into the water. 

 After laying, the puncture made by the ovipositor of the female closes, 

 so that during the following winter it is found with difliculty, but in the 

 second season of the scar it appears as a small hole surrounded by the 

 circle of dead bark under which lay the six eggs. (See fig. IS.) With 

 further growth this circular scar does not heal, but widens laterally 

 so that a series of puncture scars in their third season appear as a 

 scries of lenticular depressions in the growing twig. (See fig. 19.) 

 Many twigs are killed by being girdled with puncture scars. These 

 seem to disfigure alder bushes more often than willows, perhaps 

 because of the slower growth of the alder. The older scare run in 

 series of from 12 to 30 in number. With 6 eggs deposited in each 

 scar it would appear that the female lays from 70 to ISO eggs before 

 tiring. 



While ovipositing the pair are remarkably indifferent to enemies, 

 as both can be easily picked up by the hand. 



Though I watched carefully I found only one place along the creek 

 where ovipositing took place. This was in the alders and willows 

 along a scum-covered stagnant pool of the creek. Such pools occurred 

 about two to every mile. This was fringed by a thick growth of 

 Juncus and Scirpus, on the smooth stems of wliich were found many 

 exuviae of Archilestes. These were from 2 to 12 inches above the 

 surface of the water. The bottom of this pool was covered with soft 

 mud and the water was filled with floating masses of filamentous 

 algae, but though I spent an hour raking this pool for nymphs I 

 found none. 



Nympli. — The nymph of ArcMlestes grandis ( ?) has been described 

 by Needham* from Arizona specimens, but as my nymphal sldns 

 differ in certain minor characters from his description, I have indi- 

 cated these differences. 



The most noticeable difference is in size. They are in all measure- 

 ments about one-fourth smaller than the Arizona nymphs. The 

 following are the measurements of the Satus specimens: Length, 

 inclutUng gills, 28-31 mm.; gills, 9-10; abdomen, 14-15; liind femur, 

 6; antenna, 6; mdth of head, 5; width of abdomen, 3. 



These Satus specimens (see figs. 22-26) are among themselves very 

 uniformly marked and differ in certain points from Needham's 

 description of Arizona nymphs. The main points of their coloration 



1 Noedham, James G. New dragon-fly nymphs in the United States National Museum. Proc. U. S. 

 Nat. Mus., vol. 27, No. 1371, pp. 685-720, pis. 38-44, 11 figs, May 20, 1904. See pp. 712-713, pi. 42, fig. 3. 



