4 Tre BLOWFLIES oF NortH AMERICA 
covery and application of new characters. Therefore, only an 
abbreviated review of the introduction of characters is given. 
Development of the classification divides somewhat naturally 
into three periods on the basis of the characters largely employed 
at the time. In the first period, characters of mouthparts, anten- 
nae, wings and color were the basis of the taxonomy; in the sec- 
ond period, principally characters of chaetotaxy; and in the 
third period, the more stable characters used in the previous 
period together with others of the genitalia, immature stages, 
and biology. 
First period. Linnaeus (1757) divided all Diptera into 10 
genera on the basis of differences he found in the mouthparts. 
Three of these (Musca, Oestrus, and Conops) when grouped to- 
gether correspond roughly to the present suborder Cyclorrhapha. 
Each of these divisions contained calypterate species. The 
largest, Musca, also contained species of Syrphidae, Stratiomyi- 
dae and Bombyliidae. Linnaeus further divided his genus 
Musca into 5 groups on characters afforded by the arista. He 
was thus able to separate certain calliphorid and muscid species - 
in which the arista is plumose from some tachinid and anthomyiid 
species in which it is bare. 
Harris (1776) illustrated wing venation of flies known to him 
and divided Linnaeus’ genus J/usca into five ‘‘orders.’’ The 
first of these included the Calliphoridae, Sarcophagidae, and 
Tachinidae. — 
Dumeril (1801) divided the order Diptera into 4 families on 
characters of the mouthparts. He placed the blowflies in what 
he termed ‘‘Sarcostomes,’’ recognizing 21 genera. The Callipho- 
ridae were included in the Muscidae. In 1806 he further ex- 
tended his system, adding 1 more family and separating the 
‘“Chetoloxes’’ (which included the Tachinidae and the Musci- 
dae) from ‘‘ Aploceres’”’ (which included Bibionidae, Stratiomyi- 
idae, ete.) on characters of mouthparts and the presence or ab- 
sence of hairs on certain portions of the mouthparts. He sep- 
arated the Muscidae (including Calliphoridae) from the Tach- 
inidae on the basis of the plumose arista. 
Meigen (1803) introduced the character of the size of the 
squama by separating certain genera of flies with abbreviated 
squamae (now considered Acalypteratae) from other genera 
with large squamae (now considered Calypteratae). He also 
made use of the character of the bend in the fourth vein to sepa- 
rate anthomyiid flies from other muscoid groups. 
Latreille (1805) first subdivided the order Diptera on the basis 
of habits and immature stages as well as upon adult characters. 
