Dec. 1894.] 



INJURIOUS INSECTS AND FUNGI. 



213 



infested was unfit for table. Some of the stems were quite 

 rotten, only just the inner or " heart " part being sound and 

 white. In some instances, the leaves of the celery plants infested 

 with the larvse of PiopMla apii were mined by the Tephritis 

 onopordinis, and it appeared as if they were also feeding on 

 their sweet juices, for some of the Tephritis larvse were found 

 within the closely-packed folds of the stems. 



The liy (Figs. 2, 2(x), which belongs to the genus Fiophila of 

 the order Mttscidce, is two lines, or the sixth of an inch, long, 

 and has a wing expanse of four lines, as described by Professor 

 Westwood. Its body is dark with a light brown-coloured head. 

 The wings are white with light brown veins, and the legs are 

 light yellow. Eggs are laid by the females upon the celery 

 stems just below the leaves, which is the point from which 

 the larvae commence their mining operations. The larva is 

 about 3y lines, or slightly more than the fourth of an 

 inch in length, yellowish-white in colour, very shiny, with 

 two dark spiracles at the tail end, and from these the two 

 delicate air vessels, noticed by Professor Westwood, like silken 

 threads, run along the whole length of the body, just under the 

 skin, to the segment just behind the head, where they are con- 

 nected with two exserted appendages," which are well developed 

 and stand out clearly. The anterior end is sharply pointed, and 

 the black mouth and head are " capable of being withdrawn into 

 the subsequent segment," and this is constantly done with every 

 movement of the larva. Under the skin, on the second and third 

 segments from the tail end, there are reddish patches, at least 

 these were seen in all of the many larvae examined. 



The pupal state is assumed quickly in the celery stems, at least 

 in the first geneiations. In the last generation, the larval life 

 seems to be protracted, as larvae, together with pupae, are found 

 in very late dug celery. Some of the larvae go into the earth 

 to pupate, as may be seen from their exit holes at the base of 

 the crown of the root. 



Methods of Prevention and Remedies. 



Unfortunately, though obviously, these are but few. Spraying 

 the stems with paraffin and soft soap at the rate of one pint of 

 paraffin, and 8 ozs. of soft soap, to 10 gallons of water, or with 

 carbolic acid and soft soap, put on with a knapsack machine, 

 would certainly prevent the later generations from laying eggs 

 upon the stems, and the larvae from boring into the stems. In 

 places liable to be infested it would be well to spray as a matter 

 of precaution. 



Every particle of infested celery plants should be picked up 

 and burnt, and the trenches levelled down and the ground 

 deeply dug, so that all pieces of celery and pupae that have been 

 missed may be deeply covered. Lime, lime ashes, or gas lime 

 might be advantageously dug in. 



