NEMATOCERA. 53 
wheat or barley, about eight in a patch, glued together by a sticky 
fluid. ‘The greater number are deposited on the latest-developed 
leaves. The eggs are laid with the head end downwards, so that 
when the larvae are hatched they are prepared to crawl down the 
leaves and stem, and to establish themselves within the leafy sheath, 
generally at the second joint above the ground. 
The /arva is short, stout, cylindrical, and soft-bodied; about 
2 mm. long when young, increasing to about 3 mm. “There are 
fourteen segments, and indications of prehensile feet at the anal 
end. When first hatched the larve are transparent, showing the 
alimentary canal through the extremely thin body wall, often green 
in colour, owing to the colouring matter of plants. They change 
colour when pupating. 
The larva, when it has passed its feeding stage, develops a forked 
appendage, a horny short stem with two little projections, situated 
close to the head on the under surface of the second segment—the 
“anchor-process.” _ 
In the case of the fly now under consideration, Mr. Enock has 
made the notable discovery that the larva, after it has finished feed- 
ing on the juices of the stem, with head placed downwards and 
inwards, turns itself completely round in its third stage, bringing its 
head upwards, anchor-process outwards, and that it uses the anchor- 
process to perform this feat. - 
This turning movement takes place within the “‘puparium,” as the 
hard case, or skin, is called, which gradually forms itself around the 
larva, in its second stage, after the first, or feeding stage, is passed. 
This case is chestnut brown, and in size, shape and colour re- 
sembles a small flax-seed, so much so that this stage in the life-history 
of the fly is often called the “ flax-seed stage.” At first the puparia 
are smooth, but after a few days they become marked by longitudinal 
striations. There are also transverse markings on these “ flax-seeds,” 
showing the old segmentation of the larval body. 
The ¢ puparium is narrower and paler than the ¢. ‘The “ flax- 
seed” stage may only last five or six weeks, or the fly may remain 
in this state throughout the winter or longer. (The time of emer- 
gence greatly depends upon climatic conditions, cold greatly retard- 
ing their development.) 
The larva then works its way out of the puparium, casts its skin, 
and gradually changes into a true pupa. The ¢rue pupa is at first 
white, then pink, and becomes darker by degrees. It is oval, with 
rounded ends, the thoracic portion narrower than abdominal, limbs 
and body before emerging enveloped in separate cases. The pup 
