6 THE BLOWFLIES OF NorTH AMERICA 
of classification, and his system is used by most dipterists at the 
present time. Owing to their prominence, such bristles were often 
mentioned by earlier workers, especially Fallen, Robineau- 
Desvoidy, and more particularly Rondani. The latter introduced 
the term ‘‘macrochaeta’’ for larger bristles. Osten Sacken 
termed the system ‘‘chaetotaxy.’’ He noted that calypterate flies 
have a row of bristles across the hypopleura and that acalypte- 
rate flies do not have such a row of bristles. This important dis- 
covery has been incorrectly attributed to Girschner. 
Girschner (1893) offered a system of classification for the ma- 
jor grouping of muscoid flies which approaches the classifica- 
tion now in general use. His major divisions were based upon 
the character of the hypopleural bristles and his minor divisions 
upon other characters of chaetotaxy, supplemented by differences 
in abdominal tergites and sternites. He was the first to recognize 
the ecalliphorid flies as a distinct group, under the subfamily 
name of Calliphorinae. Various European dipterists still retain 
the subfamily status for the group. 
Brauer and Bergenstamm (1889-1894) introduced numerous 
characters of the head such as the position-of the vibrissae, the 
shape and position of the elypeus, and the shape of various 
sclerites, and they greatly extended the use of chaetotactice char- 
acters. These authors paid particular attention to the generic 
separation of calypterate flies and less attention to the natural 
relationships between genera and species. Some of the ealliphorid 
species were included by them in sections of the Sarcophagidae 
and others were included with the Muscidae. Both these see- 
tions contained members of other families as well. 
Hough (1899), the first to publish a comprehensive account of 
North American blowflies, used the system proposed by Girsehner. 
He was the first to recognize the blowflies as a distinct family. 
Villeneuve (1914, p. 256) discovered that the presence or ab- 
sence of cilia on the posterior basal portion of the remigium 
would divide the Calliphoridae into two distinct groups. He 
ealled the group with bare remigium ‘‘C. nudiae,’’ which would 
include the subfamilies Calliphorinae, Polleniinae, and part of 
the Mesembrinellinae of the present paper. The group with 
ciliate remigium he ealled ‘‘C. ciliae;’’ this would include the 
Chrysomyinae, Rhiniinae, and a few Mesembrinellinae. 
Third period. The characters which most accurately define 
the calypterate flies and the family Calliphoridae have been dis- 
covered within the past 25 years, and these discoveries are, at 
least in part, coincident with the general employment of better 
optical equipment. 
