172 THE CANADIAN ENTOMOLOGIST 



But apart from the changes due to alterations in their breed- 

 ing-places, additions to the local list of dragonflies in well-worked 

 localities are of frequent occurrence and are doubtless generally 

 due to the great powers of rapid and sustained flight possessed by 

 these insects, and the tendency of many species to wander far 

 afield from their place of emergence. This wandering tendency 

 in some species amounts to a true migratory instinct, and it has 

 been recently shown in a very interesting article by Howard J. 

 Shannon* that certain species such as Anax Junius, Libellula pul- 

 chella and Tramea lacerata, together with either insects, notably 

 the Monarch Butterfly {Anosia plexippus), follow regular annual 

 migration routes which are clcsely similar to those of birds. I 

 have never witnessed such a migratory flight, although they have 

 been frequently reported, but it may be of some interest to record 

 some desultory observations I ha\e made, which seem to indicate 

 that some of our Odonata habitually fly distances of many miles 

 during their ordinary foraging excursions, and that the occurrence 

 of large numbers of a particular species in a given locality does 

 not necessarilv indicate that they were bred from water in that 

 vicinity. They also illustrate the point already referred to, viz., 

 the frequent occurrence in a particular locality of stray individuals 

 of species not normally resident there. 



These observations were made, for the most part, at De 

 Grassi Point, on the west shore of Cooke's Bay, Lake Simcoe, 

 Ont., where I have been collecting and observing dragohflies dur- 

 ing a majority of the past 15 years, and they relate chiefly to the 

 species of ^shna, to which genus I gave special attention for several 

 years, while accumulating ' material for my monograph of the 

 group. This genus is, moreover, one that is of particular interest 

 in this connection, as the species are all large insects of powerful 

 and wide ranging flight, and are better represented than any other 

 genus of Odonata in the vicinity of De Grassi Point. 



I have described elsewhere** the occurrence at De Grassi 

 Point during certain years, of vast numbers of ^shna canadensis 

 E. Walk, and A. constricta Say, and have noted that the swarms 



* Insect migration -as related to those of birds. The Scientific Monthly, 

 vol. 3, No. .3, p. 227, Sept., 1916. 



** The N. Am. Dragonflies of the genus .(^shna, Univ. Toronto Studies, 

 Biol. Sen, No. 11, 1912. 



