74 



in the cherry orchards. One or two species are also found in Europe. The 

 genus Trypeta contains a number of gall- producing species, but there are also- 

 several that have turned their attention to fruit in this genus, of which 

 Trypeta ludens, the "orange fly" of Mexico, is a typical example. 



The Mediterranean fruit-fly is placed in the genus Ceratitis, and represents 

 a world-wide pest. A number of allied species have been described from 

 southern Africa and Mauritius. 



Some species have been described and placed in other genera, which, after 

 closer examination by specialists, may be found to belong to some of the above 

 typical groups. 



The maggots of the typical species of Trypetidce that infest fruit are so 

 much alike in general form and structure that a general description of one 

 species will define them all. There are a few minor points of difference known 

 to the entomologist such as the shape, number, and situation of the spiracles 

 that are placed on the last segment and surrounded with a rosette-like process. 



The maggots vary in colour (according to their food) from semitrans- 

 parent white to yellow of all shades to pink and red, and the average 

 length of a full-grown one is ^ an inch in length. They can be best 

 described as rather slender, naked, cylindrical grubs, tapering from the broader 

 truncate anal segment to the front of the head (or cephalic segment), which 

 comes to a blunt tip, and contains a pair of black, hard, retractile booklets or 

 jaws. With the aid of these jaws and with the power of contracting the 

 segments of the body, they can move quickly through the damaged tissue of 

 the fruit, which they tear with these curved jaws ; and also, when full grown, 

 can work their way into the soil when they leave the fruit to pupate, and so 

 are very soon out of sight if placed on loose soil. They also have the power, 

 particularly if placed on a smooth surface, of curving the ends of the body 

 round and springing up a considerable height like the " jumper" maggots in 

 cheese. 



They all feed in the same manner, commencing as soon as they hatch from 

 the eggs, to feed upon the surrounding tissue ; and in ripe fruit the infested 

 area soon spreads and forms a putrid mass extending to the centre, 

 when the fruit fills to the ground. I do not think that the maggots 

 drop from the hanging frui*-, except on rare occasions ; but as many of the 

 maggots are not fully developed when the fruit falls, they remain until fully 

 fed before they crawl into the soil beneath. 



Their action upon this tissue of different fruits is characteristic, for while 

 in the orange, peach, and soft ripening fruits it all becomes a putrid mass,, 

 in unripe peaches it is more a network of damaged tissue in the early stages, 

 and where apples and pears are attacked their mining becomes a series of 

 galleries or small chambers before the final decay. 



This is so noticeable in the work of the apple maggot in America, 

 (Ragoletis pomonella) that it is often called the " railroad maggot." When 

 full grown the maggots crawl out through the underside of the fruit, and 

 thus resting on the soil they work their way downward to a depth of J to 

 sometimes 2 inches if the soil is very loose, but usually more will be found 

 less "than an inch under the remains of the fruit. 



They do not take long to transform from the soft maggot to the oval hard 

 pupa, the outer skin of the maegot changing into a stout shell-like case of 

 yellow or reddish brown tint. Enclosed in this protective covering, the final 

 transformation to the perfect fly takes place. Then, when ready to emerge, 

 it bursts the front of the shell off and works its way up to the surface of the 

 soil, a perfect fruit-fly. 



