48 THE REPORT OF THE No. 19 



Park, AA-hich were referred by supposition to this insect, as they clearly be- 

 longed to the same genus as N. ohsoleta (Say.), the only other regional 

 species and AA'hose nymph was already known. This summer I had the good 

 fortune to come upon the same kind of exuviae upon the timbers of the wharf 

 at Go Home, where they had evidently emerged from water of considerable 

 depth, 5 or 6 feet at least. Further search revealed others on the steeper 

 parts of the rocky shores and on June 28th a special hunt for the emerging 

 imagoes was made in the early morning. After protracted search, when 

 we had almost come to the conclusion that their time for transformation 

 was over, one was at last found in a wide crevice accompanied by its exuviae, 

 and on subsequent occasions .several more were obtained. 



No imagoes could be found on the wing, however, and it became a sub- 

 ject of conjecture to us what became of them. One evening, however, some 

 time after sunset, Mr. Fraser made the discovery that they were flying about 

 the island in pursuit of May flies. Since then we took them repeatedly at 

 almost the same hour, but at no time during the day were they ever seen 

 upon the wing, except when started from a bush or tree where they were 

 resting. This is the only case I know of a strictly crepuscular dragon-fly 

 though several diurnal species, such as the Aeschnas, are known to fly until 

 dusk. 



Several otlier forms belonging to this same group of Cordulinae were 

 met with but the only ones which occurred in large numbers besid.es the 

 Tetragoneunas already alluded to, were the dainty and beautiful little 

 Dorocordulia libera, (Selys.) and the large and striking Epicordulia prin- 

 ceps, (Hag.). The former with its delicate form and slender waist, its vivid 

 emerald green eyes and dark metallic green body is one of our most exquis- 

 ite dragon-flies. Its nymph is an inhabitant of the swampy inlets and boggy 

 margins of the enclosed lakes, and here the imagoes may be found coursing 

 up and down over the M'ater or the bog, with the abdomen tilted up in a 

 peculiar way, or sunning themselves upon the leaves along the shore. 



Epicordulia princeps, (Hag.) is a species of more southern distribution 

 and hence more often seen in collections. It is peculiar among Cordulines 

 in having the wings spotted after the manner of some of the common Libel- 

 lulae, but is readily distinguished from these on the wing for it is a much 

 more restless insect, flying ceaselessly over the larger bodies of water often 

 at considerable heights, but also common enough in the rocky open woods 

 some distance from the shore. It was a very characteristic species about 

 Go Home Bay from the last week in June until about the middle of August. 



The largest and most striking of all the dragon-flies of the region, how- 

 ever, has not yet been mentioned. This is a great black and greenish-yel- 

 low Gomphine, Hagenivfi brevistyJiis, (Selys.) which suddenly appeared on 

 the Station island and elsewhere in considerable numbers. Its great size, 

 striking coloration and the peculiar way in which the abdomen is curved 

 downward in flight renders it a formidable-looking insect on the wing, 

 while its nymph is a most gorgeous creature very different in appearance 

 from other Gomphines. It is a large flat brown insect with a nearly circu- 

 lar abdomen looking more like a gigantic bed-bug than anything else. They 

 live among the roots and debris along the lower and more sheltered parts 

 of the shore, always, however, where there is considerable wave-action or 

 current. The few nymphs we found before their time for transformation 

 began died in confinement, the water in which they were kept not having 

 been sufficientlv well aerated. 



Numerous other dragon-flies were taken and the nature of their breed- 

 ing places more or less definitely determined, but time does not permit me 

 to mention more than a few of these. 



