XXIX. THE LOCUST TREE. 459 
two upper shorler and cohering or approximate. The banner 
of the corolla is ample, the keel obtuse. The stamens in 2 
bundles, deciduous. The style is bearded next the free stamen. 
The fruit is a many-seeded pod, with the seed-bearing edge 
margined, and with thin and flat valves. 
The locust trees, particularly the Common, are subject to 
the assaults of many insects. ‘The leaves of the common locust 
serve as food and habitation to the caterpillars of the Tityrus 
skipper, a large, brown butterfly with honey-yellow spots, 
(Harris's Report, p. 224, where is found an interesting account 
of the habits of the caterpillar). The bark is punctured and 
the sap sucked by the two-spotted tree-hopper, (Wembrdcis bi- 
maculata, ib. p. 179). The pea-weevils, (Bruchus pisi, ib. p. 
55), lay their eggs in the seeds as they do in those of the pea 
and other leguminous plants; and the grubs of an Apion beetle, 
(ib. p. 59,) inhabit the pods and eat up the seeds. ‘The grubs 
of the painted Clydus beetle, (ib. pp. 86 and 295,) burrow in the 
bark and devour the soft inner portion, in autumn, and in spring 
they bore through the sap-wood, more or less deeply into the 
trunk, which they traverse by many winding and irregular, 
upward passages. A small reddish caterpillar (supposed by 
Dr. Harris to belong to one of the A%gerian sphinges, or to one 
of the Bombyces, see p. 295 of his Report), lives in the pith of 
the small branches and trunks of very small trees. The irri- 
tation causes the twig to swell and become spongy in the parts 
affected, and easily to break off at these places. The large ca- 
terpillar of the locust tree carpenter-moth, (Xyleutes Robinia, 
ib. pp. 296—7), bores the tree in various directions, appearing 
to prefer old and full grown trees. For full accounts of these 
several enemies of the locust tree, which threaten, if not checked, 
to exterminate the tree, 1 must refer to the admirable Report of 
Dr. Harris. 
Two species of locust, besides the Common, are natives of 
the southern parts of the country and may be cultivated here: 
R. viscosa, the Clammy-barked locust, which is a small tree, 
with large, showy, pale pink flowers; and R. Atspida, the Rose 
Acacia, a very beautiful flowering shrub. 
