10-i THE CANADIAN ENTOMOLOGIST. 



(2) A. Forbesii, Rob. — ?. April 19. Beside the colour of the pubes- 



cence, Forbesii is distinguished from rugosa by the smaller and 

 more numerous ridges on the base of the metathorax ; about 20 in 

 Forbesii, about 12 or 14 in rugosa. The abdominal hair-bands of 

 Forbesii may be practically obsolete. 



(3) A. Cressonii. Rob.— $ , April 30 ; 9 , April 19. The c^ is not quite 



typical in the face-markings. 



(4) A. bipt0ictata, Cress. — Many males, April 19 to May 18. 



(5) A. vidua, Sm. — April 21 to June 18. Very many. None are var. 



errans (A. errans, Sm.). At Olympia, Washington State, Mr. T. 

 Kincaid takes the typical form and var. errans together, the variety 

 being the most numerous. 



(6) A. fimbriata, Sm. — ?, Sept. 9 and 15. $, Sept. 9. The male is 



smaller and more slender than the V ; face wholly dark, with 



long yellow hair ; flagellum faintly ferruginous beneath ; process 



of labrum bifid ; apex of abdomen with yellowish-white hair ; 

 pubescence of legs pale. 



BOOK NOTICE. 



Some Considerations on the Nature and Origin of Species. — By 

 J. W. Tutt, F. E. S. 



This is the title of the presidential address delivered before the City 

 of London (England) Entomological and Natural History Society. De- 

 cember, 1897, published in a pamphlet of 20 pages. Mr. Tutt interest- 

 ingly reviews the recent theories as to the causes of species formation, 

 touching on the presence of variation in organic beings, action of natural 

 selection, origin of local races by adaptation to differing environment, 

 etc., and comes to the conclusion that all generic and specific characters 

 are due to the past or present action of natural selection. Compara- 

 tively fresh points are made in that specialization of genital organs does 

 not necessarily accompany other specialization, and that isolation may 

 be brought about by difference in time of emergence, difference in habit 

 or in the hours of mating, as well as by geographical conditions. 



Mr. Tutt does not believe that climate, food, sexual selection (in 

 insects at least), isolation or laws of growth can produce specific charac- 

 ters ; all such must be utilitarian. This is the position so ably defended 

 by Wallace, but nevertheless certainly untenable. 



The reviewer would refer Mr. Tutt to the case of Datana, where all 

 the specific characters seem so evidently due to the action of isolation 

 alone, as most recently lucidly explained by Romanes. In this case the 

 isolation is due principally to different food plants. 



Harrison G. Dvar. 



Mailed April ist, 1898. 



