48 DIPTERA OF AUSTRALIA, 



CHARACTERS OF THE FAMILY. 



The Transformations. 



I. Ovum. 



The egg is longer than broad, the ends rounded, orange-red, 

 yellow, or whitish. The nidus for the egg may be any part of a 

 plant according to the habits of the species ; some appear to 

 simply deposit the eggs on the surface, many to sink them into a 

 puncture in the surface, and others singly or grouped together 

 under the bark of lai'ge trees. The time when the eggs are laid 

 is probably generally early morning or in the evening. A few 

 days as a rule elapse before the young larvse emerge, but this is 

 to a great extent influenced by the weather ; in some cases the 

 hatching is accomplished in a few hours. P)-of. Loew is of opinion 

 that species having ])ut one yeai-ly generation remain a consider- 

 able length of time in the egg state. 



II. Larva. 



The young larva is of an elongate slender form, almost trans- 

 parent ; and the colour of the same species visibly changes with 

 the increase of age, varying from orange or pinkish through 

 different shades of red, or perhaps becoming light yellow or 

 whitish. The body is composed of 14 segments, of which the 

 head is regarded as the first. Between this and the thoracic 

 segments is isituated a joint which has been considered as either 

 belonging to the head or to the thoracic region. Three segments 

 are allotted to the thoracic, and the nine remaining to the 

 abdominal division. Stigmata placed one pair on the first thoracic 

 segment, and a pair on each of the abdominal .segments except the 

 last, appearing as moi-e or less nipple-shaped prominences. The last 

 two sometimes project considerably more than the preceding ones, 

 and are occasionally removed towards the middle of the segment. 

 Integument diaphanous, generally finely shagreened. 



