INSECUTOR INSCITI^ MENSTRUUS 13 



instance, typically a forested country, the Canadian fauna oc- 

 curred everywhere; but there are open spaces in the valley and 

 here Acdcs spencerii and A. currici could always be found, 

 though never seen in- the forest. Likewise at Saskatoon, Sas- 

 katchewan, a typically prairie region, patches of bush occur in 

 hollows in the prairie and along the river, and in. these A. 

 punctor was not infrequent. In addition, there exists a group 

 of species whose habitat may be said to be the prairie forests. 

 Mr. Knab, who had experience with these forms in 1907, was 

 of the opinion that A. fletcheri was a prairie species and A. 

 riparius a forest species. I am convinced that both occur to- 

 gether, roaming over the prairie in the general vicinity of bush, 

 and extending a certain distance into the true forest. More- 

 over, the two are indistinguishable in the female adult and con- 

 stitute a pair of species as in the case of A. fitchii and A. ex- 

 crucians. They are easily separable by the male genitalia, but 

 from localities where only females are at hand I have found it 

 impossible to say which species was before me. 



Exact determinations from the female adult alone of the 

 species with black tarsi, also, are not always possible, for. while 

 the mass of specimens runs true to type, variations occur that 

 overlap specific limits. For example, dark examples of punctor 

 cannot always be told from intrudens; blurred examples of 

 laaarensis cannot be told from the double-striped form of 

 punctor; pale lacarensis and dark diantaeus are not separable; 

 small pionips cannot easily be told from large, well-marked 

 diantaeus; decticus runs into lasarensis on the one side and in- 

 trudens on the other, so that there is a complete circle of 

 gradations between these six species. This affords a margin of 

 error in naming the captured females that I have not been able 

 to guard against. 



The specimens collected along the Albany River by Mr. H. 

 N. Awrey, at the instance of Dr. C. Gordon Hewitt, are of 

 especial interest because they include the locality, Martin Fall, 

 Ontario, formerly known as "St. Martin's Falls, Albany River, 

 Hudson's Bay," which is the type locality for punctor Kirby, 



