86 INSECUTOR INSCITI^ MENSTRUUS 



largely created by artificial conditions — most of my larvae of 

 aboriginis occurred in the town proper. The dark pools in the 

 stream-beds in the forest, which are heavily infested with 

 Eucorethra, yielded no A'edes larvae, one third-stage skin only 

 rewarding search, although these would seem to be the only 

 habitat of aboriginis in a state of nature. Civilization, if not 

 too highly organized, would seem to be beneficial to the species. 



Total, 382 specimens : Prince Rupert, British Columbia, 

 May 9-June 17, 1919 ; Cape Fanshaw, Alaska, June 32, 1919. 



Also in Doctor Hewitt's collection. Royal Oak, British Co- 

 lumbia, May 4, 1917 (R. C. Treherne). 



These three species, cyclocerculus, leuconotips and aboriginis, 

 with hexodontus of the Californian Sierra Nevada range and 

 punctor of the Canadian fauna, form a closely allied group. 

 The first two inhabit typical muskeg pools in the northern 

 rainy Pacific strip ; aboriginis occupies drainage or casual, 

 often dirty pools in the same general region, but extends south- 

 ward over western Washington ; hexodontus occurs in the 

 Californian mountains, inhabiting open marshy pools, often 

 much of the typical muskeg type, while punctor extends 

 throughout the Canadian fauna from the Atlantic to the 

 Pacific. 



On colorational characters, the species group thus : 



Mesonotum typically with single quadrate median dark stripe, 



punctor Kirby 

 Mesonotal stripe divided. 



Typically, median and posterior-lateral stripes equally developed, 



aboriginis Dyar, leuconotips Dyar, hexodontus Dyar 

 Posterior lateral stripes darker and more distinct than the median, 



cyclocerculus Dyar 



On genitalic characters the grouping is as follows, replacing 

 dichotomy 21 of my table (Ins. Itis. Mens., vi, 78, 1918) : 



Spine of basal lobe of side piece stronger than accompanying setse, 



but not strongly diflferentiated punctor Kirby, aboriginis Dyar 



Spine of basal lobe much stronger than the accompanying slender 

 setae and well differentiated, 



hexodontus Dyar, cyclocerculus Dyar, leuconotips Dyar 



