548 
DIPTERA. 
may look like the third joint and its continuation (arista) is really made 
up of several joints or segments joined together. It may be noted that 
when, as in many Brachycera, the “ arista ” is thick and terminal, it 
is generally called a “ style,” to distinguish it from the very thin 
usually dorsal arista of the Cyclorhapha. 
Putting what has been said above into tabular form, we have— 
Orthorhapha, with pupa generally 
free, the fly emerging by a split 
along the top of the thorax. 
Cyclorhapha, with pupa enclosed 
in last larval skin, the end of this 
being burst open by the fly on em¬ 
erging. 
(1) Nemocera including mosqui¬ 
tos, gnats and the like, with many- 
jointed antennae and four or five- 
jointed palpi. 
(2) Brachycera including the big- 
horse flies (‘ ‘ Dans ’ ’) and a variety 
of others, with palpi of not more 
than two joints and antennae of 
various forms intermediate between 
Nemocera and Aschiza, but 
generally showing at least traces 
of more than three joints or seg¬ 
ments. 
(3) Aschiza including many 
hovering flower-flies, with frontal 
lunule but without frontal suture. 
Antennae simple, 3-jointed with 
arista. Palpi unjointed. 
(4) Schizophora including house¬ 
flies, bluebottles, etc., with lunule 
and suture. Antennae simple, 3- 
jointed with arista, as in Aschiza. 
Palpi unjointed. 
To these we will now add two more groups, whose members can 
generally be recognized without difficulty. 
(5) Pupipara including the well- 
known crab-like dog-flies. Parasitic 
sometimes wingless insects of 
curious shapes, flattened, with lea¬ 
thery skin. They lay no eggs, but 
