INTRODUCTION. 
547 
tematieally important structure in the shape of a minute sclerite just 
above the base of the antennae, called the frontal lunule (fig. 405) which 
is characteristic of all the Cy- 
clorhapha. Apart from these 
three families the rest of the 
Cyclorhapha consists of a vast 
number of species possessing 
both lunule and suture, and 
hence known as Cyclorhapha 
4 4 Schizophora 5 ’ (he..; 4 'pos¬ 
sessing suture ”). House-flies 
and blue bottles belong to 
this group. The Cyclorhapha 
as a whole are also distinguish¬ 
ed by their antennae having 
not more than three joints, the 
third joint showing no signs of 
being segmented or made up of 
more than one piece, while it 
bears on its upper side an 
“arista” (fig. 351) which is 
quite thin and hair-like and 
frequently plumose or pube¬ 
scent. The palpi are unjoint¬ 
ed. The Cyclorhapha are 
Fig. 350,— Head of muscid (cyclorhapha) just 
EMERGED FROM PCPARIUM, SHOWING ABOVE 
THE ANTENNiE THE HALF-DEFLATED “ FiTLI- 
NUM.” 
thus divided into two groups, the Aschiza and Schizophora. The 
Grthorhapha are likewise divided, but here the division is based 
mainly on the structure of the antennae. The first group, the 
Grthorhapha “ Nemocera ” (i.e., “thread horn”), generally 
have 4-jointed palpi and long antennae usually composed, of a dozen or 
more similar freely-jointed segments, while the second group, the Grtho¬ 
rhapha Brachycera (i.e., “ short-horn ”) have palpi of not more than 
two joints, and short antennae which show various grades between the 
many-jointed Nemoeerous antennae such as that of mosquitos or Simu- 
lium (fig. 351) and the simple short three-jointed antenmc of the Cyclo¬ 
rhapha. From the Oyciorhaphous antennae those of the Grthorhapha 
Brachycera differ in that they usually show pretty clearly that what 
