330 LIFE STORIES OF AUSTRALIAN INSECTS. 



to a position at its base instead of retaining its 

 terminal position. (Plate 40, Fig. 5.) The interme- 

 diate t3^pe (Plate 40, Fig. 7 b and c) varies; it may 

 have fewer joints than the plumose type, and usually 

 tapers to a point. Example, the robber fly 

 (Asilidac). 



The mouth (Plate 41, Fig. 1) is very variable, 

 ]3ut it is formed for suction and not for biting and 

 chewing. Most usually it consists of six elongate 

 bristles or stylets, and these can be placed in a 

 sheath, which is a pseudo tube — that is, it is open 

 and simply enfolds the stylets. The whole pro- 

 boscis can be retracted and placed in a cavity 

 under the head. By means of these stylets, which 

 are placed all together, the medium is pierced and 

 the liquid is drawn up. The house fly and blow 

 fly have a purely sucking mouth. There are no 

 stylets, and the tip of the proboscis is produced 

 into a broad lip. (Sec Plate 40, Fig. 4.) 



Life History. 

 The larva (Plate 40, Fig. 2) is a legless grub — 

 the typical '^maggot." It differs from a caterpillar 

 in having no legs and no anal claspers. It is 

 smooth in most cases and a creamy colour. The 

 head of a maggot is very small, and can be with- 

 drawn and hidden. In some groups of flies, the 

 head of the maggot is not clearly defined. The 

 most conspicuous part of the head of the larva is 

 the pair of dark, strong jaws. Many maggots can 

 jump by curling up the body and then straighten- 

 ing it. They feed on vegetable or animal matter, 

 and are often parasitic on living animals, such as 



