90 MARINE AND FISHERIES 



5 GEORGE v., A. 1915 

 Sjrmpetrum obtrusum (Hagen) Kirby. 



This common form appears considerably earlier than the other species of 

 Sympetrum, specimens having been observed at least as early as July 1, 1912. 

 At Lake Simcoe and southward, they appear before the end of June. The season 

 for emergence is somewhat protracted and irregular, tenerals being seen as late as 

 July 31. They fly until late in the season, several pairs in copula having been 

 taken on Aug. 26th, 1912. 



The adults are found in the same localities as *S. costiferum and vicinum, but, 

 as we have not found the nymph in this district we are unable to give anything 

 distinctive as to the nature of its breeding-ground. Stray specimens of the imagos 

 have occasionally appeared on the Station Island, where they certainly do not 

 breed. 



It is somewhat remarkable that the closely allied species S. rubicundulum, one 

 of the commonest and most generally distributed of Odonata in Eastern North 

 America, is wholly absent from the Go Home District so far as we are aware. 



Sympetrum corruptum (Hagen) Kirby. 



On Jiily 14, 1912, this species appeared very unexpectedly on the low sandy 

 eastern end of the Giant's Tomb Island. The island is divided here by a narrow 

 channel, close to which, on the outer side, is a shallow pond or lagoon (Fig. 35). 

 It was about the margins of the channel and lagoon, especially the former, that 

 Sympetrum corruptum was observed. They were flying about from place to place, 

 sometimes hovering over one spot, sometimes settling for a moment on the wet 

 sand. They were so shy that it was almost impossible to get within striking dis- 

 tance, and more than an hour of patient effort was spent before one was secured. 

 Two males and one female were all that were taken, all fully mature and in good 

 condition. 



This species was previously known from Ontario only by a single specimen 

 taken at the Humber River (Walker '06) . It is not known to occur east of this 

 province, but it is common in the Prairie Provinces and also occurs in British 

 Columbia. 



The nymph has been described by Needham ('03). 



Libellula quadrimaculata Linne. 



This wide-spread circumpolar species is fairly common, but by no means 

 abundant at Go Home Bay, where it frequents marshy bays and inlets. June 18 

 is the earliest date on which the adult was observed in 1907, while in 1912 it ap- 

 peared somewhat earlier, but the exact date was not noted. It was more numerous 

 during the latter than the former year. 



A remarkable assemblage of this species was met with on June 27, 1912, on 

 a small island in the open water of Georgian Bay, abut 3^ miles from the eastern 

 coast. On this island, which has already been described (vide p. 67) there is a 



