. A text-book of agricultural zoology. Zoology, Economic. 216 DIPTEEA OE TRUE FLIES. The Onion Fly (Phorbia cbpetorum). One of the most serious difficulties the onion-grower has to contend with is the Onion Fly, whose larvse cause the maggot in onions and their speedy decay. The onion fly is an afehy- grey fly with black bristles and hairs, and with three black stripes on the thorax; the abdomen has a row of large black spots along it; the face is silvery-whjtCj and the antennae are black; the female has a yellow facej and is generally more ochreous in colour. The onion fly appears in April an
. A text-book of agricultural zoology. Zoology, Economic. 216 DIPTEEA OE TRUE FLIES. The Onion Fly (Phorbia cbpetorum). One of the most serious difficulties the onion-grower has to contend with is the Onion Fly, whose larvse cause the maggot in onions and their speedy decay. The onion fly is an afehy- grey fly with black bristles and hairs, and with three black stripes on the thorax; the abdomen has a row of large black spots along it; the face is silvery-whjtCj and the antennae are black; the female has a yellow facej and is generally more ochreous in colour. The onion fly appears in April and May, and has several broods during the year. The female lays her ova on the neck of the young onions, and later on in the year. Pia. 108. —Oniok Flt (PhorUa cepetorum). a and b. Larva, nat. size, and magnified ; c and d, puparia : e, imago. (Whitehead.) on the onion itself. The young maggots at once eat their way into the onion and feed off its contents until it is quite hollowed out. Small plants are usually killed rapidly, but large onions remain some time in a diseased state When an onion is destroyed, if the maggots are not mature they leave it and pass to the next onion through the ground. Pupation takes place in the ground, and in the decaying onions,—the pupa being in a chestnut-brown puparium case, as in ail the Proboscidea. At the end of the year the larvae of the last brood all pupate, and pass the winter as pupae in the ground, some few being har-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Theobald, Frederick Vincent, 1868-1930. Edinburgh and London, W. Blackwood and sons
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1899
