174 THE CANADIAN ENTOMOLOGIST 



The list of our Hydrophilidce is both short and unsatisfactory; 

 the latter because so many species are in doubt. Our two largest 

 species, Hydrophilus triangularis Say. and Hydrocharis ohtiisatus 

 Say., are common at light, and the latter is frequently taken by 

 dredging. Two or three species of Helophoriis and Hydrochus 

 may be found in every slough or ditch among weeds or decaying 

 vegetation. Strangely enough, however, I have never taken 

 Helophorus tuberculatus Gyll. except on the wing. 



Berosus striatus Say., Philhydrus hifidus Lee. and hamiltoni 

 are all common, one or more of these species appearing in almost 

 every wet situation. 



In conclusion, I should like to express my gratitude to Mr. 

 C. H. Roberts, Mr. Chas. Liebeck and Dr. H. C. Fall for the gener- 

 ous and ready assistance they have given me by identifying my 

 material. 



THE RE-DISCOVERY OF AGRION INTERROGATUM, 



SELYS. 



BY E. M. WALKER, TORONTO. 



In the "Synopsis des Agrionines" (Bull. Acad. Royale Belg. (2) 

 XLI, 1876, p. 1254) Selys described Agrion interrogatiim from a 

 single female taken in "Saskatchewan, Hudson Bay Territory." 

 The description is a translation from Hagen's manuscript and the 

 type specimen is in the Hagen collection at the Museum of Com- 

 parative Zoology, Cambridge, Mass. 



Since this description was published, 39 years ago, this species 

 has not been noted, and there seemed but little possibility of its 

 ever being recognized with certainty from the description, as the 

 latter was based upon a single female, the last seven abdominal 

 segments of which were missing. 



During a trip to the Pacific Coast, in 1913, I spent two days 

 at Nipigon, Ont., and here I captured a pair in coitu of an entirely 

 unfamiliar Ccenagrion ( =Agrion Auctt.) and soon afterwards I 

 took another female. These were all I saw of this species until 

 the following year, when I came across it again at Spruce Brook, 

 near the west coast of Newfoundland. They were very scarce 

 and I succeeded in taking only four males in all. 



June, 1915 



