406 THE CANADIAN ENTOMOLOGIST 



Philanthus vertilabris var. completus, n. var. 



Male similar in markings to type, but the bands of abdomen 

 beyond that on the second segment are all much broader 

 than in normal eastern form. Sculptured as in typical 

 form; the upper yellow face mark much larger than vertilabris, and 

 its upper edge not so much emarginate; in the wings the second 

 -submarginal cell has its upper basal side twice as long as the lower 

 basal side. In the new Mexico table it runs to P. cockerelli, from 

 which it is separated by different markings. 



Length 12 mm. 



From San Diego Co., California (Van Duzee). 



FIELD NOTES AND QUESTIONS. 



MiGRATixG Notes on the Milkweed Butterfly, 



Anosia plexippus. 



BY F. M. WEBSTER, WASHINGTON, D. C. 



For a number of years the writer has been able to record the 

 banding together of this butterfly as observed by him at various 

 points in the United States. Supposedly these gatherings are 

 preparatory to the annual southward autumnal migration of the 

 species. 



The present year, 1915, my son, R. L. Webster, observed one 

 of these gatherings near Ames, Iowa, on August 30th; an excep- 

 tionally early record, as such assemblings together do not usually 

 occur until September or October. 



The writer observed a swarm of these butterflies near Water- 

 man, DeKalb County, Illinois, on September 18, a little north of 

 the latitude of Ames, but some two hundred and seventy-five miles 

 farther east. 



It would seem that there is no general uniformity in the dates 

 of the congregating together of these detachments and it would be 

 exceedingly interesting to learn just what laws, if any, regulate 

 the collecting together and of the different swarms, and if they 

 resemble in any way the systematic migrations of birds. 



