AN ENCYCLOPADIA OF HORTICULTURE. 189 
Insects—continued. 
membranous, and hidden under the front ones. The latter 
have the half nearer the body leathery, that farther from 
the body membranous, giving the appearance of the wings 
being in halves, whence the name Hemiptera, or half- 
winged insects. The name Heteroptera refers to the 
dissimilar appearance of the two halves. In this sub- 
order, many of the species are more or less parasitic; 
8 ae 
FIG. 314. FROG HOPPER, showing Larva, Frothy Secretion, 
: and perfect Insect. 
while among those that feed on plants, there are few that 
can be said to be conspicuously hurtful. 
Homoptera have the wings all membranous and naked, 
with few supporting nervures, and often resemble small 
Hymenoptera in general aspect (see Fig. 313). A great 
many species are wingless, or, at least, have wing- 
Fic. 315. GRAPE OR VINE LOUSE, showing (4) Infested Vine 
Root ; (B) Portion of Leaf, with Galls ; (C) Subterranean Form 
of Female (magnified), 
less individuals as well as winged (see Figs. 313 and 
315). The name Homoptera refers to the front wings 
being alike throughout (see Figs. 313 and 314). The 
insects are mostly very small, but include many injurious 
forms. See also Aphides, Frog Hopper, Grape 
Louse, and Scale Insects. 
INSECTS, FERTILISATION BY. See Fer- 
tilisation by Insects. 
INTEGERRIMUS. Entire; perfectly free from 
division of the margin or other part. 
INTERNODES. The intervening space between two 
nodes. : 
INTERPETIOLAR. Between the petioles. 
INTERRUPTED. Not continuous. 
INTRORSE. Turned towards the axis to which it 
appertains ; e.g., an anther when its valves face the centre 
of a flower. 
INULA (the old Latin name used by Horace, &e., 
said to be another form of Helenion). ORD. Composite. 
A genus comprising about fifty-six species of hardy 
Inula—continued. 
herbaceous plants, natives of Europe, Asia, and Africa— 
few being found between the tropics. Flower-heads yellow ; 
rays 
with 
rarely white; involucre hemispherical, imbricated, 
the scales spreading at the points; ray-florets 
Fig. 316. INULA GLANDULOSA. 
numerous, ligulate, linear; disk-florets very numerous, 
perfect, tubular; receptacle flat, or nearly so, areolate or 
honeycombed. Leaves radical or alternate, entire or 
7. 
Vk 
Fic. 317. INULA HELENIUM. 
serrate. Only a few species of this genus are worth 
growing. They are of very easy culture in common 
garde: 
n soil. Some of the more vigorous are suitable for 
