298 Macieay Memorrat Vouume. 
suction by means of the sucking-bulb, at the same time thrusting forth its spear by 
means of the muscles attached to its three-bulbed base. The cells of the epidermis of 
the rootlet having been thus pierced are sucked dry, and at the aperture thus made 
|" a am other and deeper cells are similarly attacked. 
| ‘\ 
a 
Iv 
s v 
Fie. 8.—Tylenchus radi- 
cicola. 
Continuing this line of action, the little worm 
makes its way into the rootlet, where its 
presence soon excites abnormal growth, re- 
sulting in galls, which vary in size, according 
to the species of plant attacked, from the 
size of a pin’s head to that of a large walnut. 
In consequence of these attacks, many culti- 
vated crops, as, for instance, potato, cabbage, 
banana, pea, bean, members of the melon 

Fic. 7.—Neck of the 
worm shown in Fig. 
5 more highly mag- 
nified. 
s, spear; b, median 
I,a young larva. II,a 
half-grown female. III, 
a full-grown female. IV, 
two eggs. v, the vulva; 
s, the segments of the egg 
sucking-bulb ; y, ven- 
tral excretory pore. 
after the first division. 
First three figures magni- 
fied twenty-five times, 
the others three hundred 
family, beet, parsnip, radish, tomato, plum, 
apricot, peach, almond, grape, and many 
times. others suffer much or succumb altogether. 
The worm isa veritable pest in many parts of New South Wales, Queensland and 
Victoria. 
Soon after the young worm loses its tail the sexual organs begin to develop. 
The female continues to grow stouter and finally becomes a flask-shaped sac devoid 
of anus and with a terminal vulva. The two-parted female sexual apparatus develops 
enormously, and at last almost completely fills the body-cavity, the eggs contained 
in it numbering several hundred. These undergo segmentation 2 
utero, and are deposited (in the tissues of the attacked plant) con- 
taining already well-developed embryos. 

Fic. 9.—Male of 
radicicola 
I, male worm magnified 60 
times II, head of the same 
worm magnified 450 times. 
III, male shedding its skin for 
the last (?) time. IV, cross-sec- 
tion of the posterior part of the 
body. V, side view of the same 
part. VI, side and ventral 
views of the tail-end. s, spear; 
b, median sucking-bulb ;_ sz, 
spermatozoa ; c, cuticle ; 7, in- 
testine ; v, seminal vesicle ; d, 
posterior end of the ejaculatory 
duct ; ps, spicula or penes; a, 
anus. 
Tylenchus 
The male worm, however, instead of con- 
tinuing in the path of development followed 
by the female, returns to a slender adult form, 
having the following dimensions and charac- 
up he 137 Me (98:7; e = 
ters 5 s3-3 1 133mm. Cuticula with about 

five hundred transverse striz; neck conoid, 
head truncate ; lips six, distinct ; spear stout ; 
cesophageal tube one-fourth as wide as the 
neck, lined with thick glistening chitin; median 
bulb ellipsoidal, two-fifths as wide as the neck, 
with-a large distinct chitinous central part ; intestine two-thirds as 
wide as the body, its cells closely packed with granules ; rectum twice 
as long as the anal body-diameter ; tail obliquely hemispherical-conoid ; anus incon- 
spicuous ; bursa none; spicula acute, linear, nearly straight, wider and fusiform in 
