314 ^ THE CANADIAN ENTOMOLOGIST , 



3. Wings normal 105G lateralis Cv. 



Ottawa, G, VI, on PotentUla, etc. 

 First recurrent nervure fails to reach submarginal norxure in 

 either wings maculalum Proy. 



4. Ventral segment 3 depressed in centre at apex; length 8 mm. 



1057 {'^monticola Cr.) 



One specimen, Vernon, B. C. (Venables). 

 Ventral segment 3 raised in centre at ape.x, length less 5. 



5. Third ventral segment with low tubercle at apex in centre, the 



tubercle slightly produced beNond margin, bands un segments 

 1 to 5 all about e(}ually interrupted in middle, second sub- 

 marginal cell longer than first, abdomen much longer than 



broad; length 4 to 7 mm 10.58 siibemarginata Cr. 



N. B. to Man., Ottawa, 1, W. 

 l^ird \entral segment broadly raised at apex in centre, not 

 produced, pale skin bands on segments 1 to 5 more widely 

 interrupted on basal segments than on apical segments; on 

 segment 5 they usualK' meet, abdomen almost as broad as 



long l{)o\) fa'deralis Cr. ( — uitida Cr.) 



Ottawa, 6, VI, Toronto. 

 (In the compilation of the above tables the author is indebted for 

 help to Mr. J. C. Crawford of Washington.) 



A CURIOUS TRAP FOR DRAGONFLIES. 



In a pasture just south of De Grassi Point, Lake Simc(je, 

 Ont., there is an artesian well, consisting of an iron pipe driven 

 perpendicularly into the ground to the recjuired depth' and pro- 

 jecting about 2J^ feet above the surface. It terminates in a 

 curved joint, from which the water strikes the ground almost 

 vertically, with sufficient force to drill a hole about 10 inches deep 

 into the soil. The water then spreads into" a shallow puddle, 

 used as a watering place for cattle and geese. Some of it, however, 

 passes under a nearby fence into a ditch dug along the edge of a 

 cultivated field. This ditch, which is not more than about a foot 

 Avide, is the haunt of a number of dragonflies, some of which 

 probably breed nowhere else in the vicinity of De Grassi Point. 

 The water is for the most part covered with duckweed {Lemna), 



September. 191C 



