42 THE CANADIAN ENTOMOLOGIST. 



but where such doubt exists, I have, in the following list, explained the 



circumstances as best I can, quoting the authorities who have seen my 



specimens, and, where my own opinion differs from theirs, stating grounds 



for my verdict. Breeding from the egg would doubtless clear up many 



doubts, as well as cause many surprises, but, unfortunately, I have never 



been able to spare the necessary time and attention for such useful 



experiments. It is also much to my regret that I have never been able to 



spend much time collecting after the middle of July. On this account I 



am very poorly represented in some obscure species, notably in the genus 



Argynnis. This is the more unfortunate by reason of some of the 



representatives of that genus here in the West being very difficult to place. 



My thanks are due to Prof. J. B. Smith, who has done all in his power to 



assist me in naming myNoctuida? ; also to Messrs. Elwes,W. H. Edwards, 



Drs. Ottolengui, Fletcher, Skinner, Holland, and others who have from 



time to time named specimens for me. Mr. Bean worked the Laggan 



district for several years, in the mountains near the western boundary of 



Alberta, and a few of my records are on his authority. Mr. Sanson, of 



Banff Museum, and Mr. P. B. Gregson, of Lacombe, about a hundred 



miles north of Calgary, have also kindly assisted with supplementary 



lists. 



(To be continued.) 



ON SOME DIPTERA BRED FROM COW-MANURE. 



BY L. O. HOWARD, WASHINGTON, D. C. 



In the summer of 1889, while engaged in an investigation of the 

 habits and life-history of the horn fly of cattle (Haematobia serrata), the 

 writer at various times brought to Washington from different points in 

 Virginia, large quantities of cow-manure collected in the field, and eventu- 

 ally succeeded in working out the complete life-history of the horn fly, as 

 displayed in Insect Life, Vol. II., No. 4, October, 1S89. In this article 

 the statement is made, in concluding, that the observations were greatly 

 hindered and rendered difficult by the fact that fresh cow-dung is the 

 nidus for a number of species of Diptera, some about the same size and 

 general appearance as the horn fly, and that no less than twenty distinct 

 species of flies had been reared from horse- and cow-dung, mainly the 

 latter, and six species of parasitic insects as well. The plan finally 

 adopted of securing the isolation of the horn flies was to remove the eggs 



