THE CURRANT FLY. 2.J 



LIFE HISTORY. 



The flies emerge the last of May or early in June, depending 

 on the season and location of the bushes. The time of emerg- 

 ence extends over about three weeks. The flies live about a 

 month. They mate soon after they emerge and begin laying 

 eggs, selecting the larger currants at the base of the bunches 

 first and depositing eggs in the others as they attain sufficient 

 size until the eggs are all deposited. It often happens that 

 several currants at the ends of the bunches are not affected and 

 later develop good fruit. Usually only one egg is laid in a 

 currant. The flies are capable of laying at least two hundred 

 eggs and as they live only about a month must lay several 

 every day. The fly when about to lay an egg lights on the 

 currant and in a nervous, restless manner keeps the wings in a 

 constant fanning motion. She often examines several currants 

 before finding one to her fancy. Usually one of the large 

 currants in the upper part of a bunch that is in the shade is 

 selected. The eggs are laid one in a place at one side of the 

 puncture made by the ovipositor and so close to the skin of the 

 currant that they can usually be plainly seen through it. The 

 eggs are opalescent, white, oblong and pedicilate and about 

 one twenty-fifth of an inch long. They soon hatch into a 

 white footless maggot with thirteen segments to the body, the 

 head armed with a pair of black parallel retractile hooks, the 

 rasping organs of the maggot. The larva requires about three 

 weeks to mature, when it is about one-fourth to one-third of 

 an inch long. 



When hatched the larva is about one-twenty-fifth of an inch 

 long and as soon as it emerges from the egg begins to travel, 

 often leaving a delicate light colored trail close under the skin 

 which can be seen through it. After traversing from a third 

 to a half the distance around the currant it locates, entering in 

 most cases one of the seeds, disappearing entirely within it. 

 Sometimes the larva locates near the puncture and sometimes 

 the exit hole is on the opposite cheek from the puncture. As 

 it grows the head finally protrudes from the seed as shown in 

 the Plate, Fig. 7. After feeding upon the contents of a seed 

 and having grown too large to find lodgment within it, it 



