Bulletin 151, Truck and Garden Insects


worms (fig. 109) are 3 or 4 inches long. Near the posterior
end there is a curved spine which suggests the name "horn-
worm." This is wrongly supposed by many to be a poisonous















 FIG. 109.-Southern hornworm. Natural size. (From Fla. Agr. Exp. Sta.
 Bul. 48.),

sting. The insect is entirely harmless. When the worms"
are full-grown they enter the ground to a depth of 3 or 4 inches,
and change to the dark red-brown pupae. The projecting
tongue-case is characteristic of the pupae of this family of
moths and enables them to be told at a glance; it suggests a
handle to the pupa. (See fig. 110.) The pupae from the first
brood of larvae appear in North Florida in July.
 Natural Enemies.-The hornworms are held .
in check fairly well by their natural enemies.
Among the latter are tachina-flies, which lay
their eggs on the caterpillars, and also a minute
hymenopterous insect (Apanteles congregatus).
The eggs of these parasites hatch into minute
grubs which burrow into the caterpillar and
live on its fatty tissue but avoid the vital or-
gans, grow to full size and then emerge to form
their pupae on the outside of the host. (See
fig. 111.) These parasites have been given promi-
nent mention, because it is important that these
parasitized specimens be not crushed or other-
wise destroyed. Parasitized worms should be FIG. o10.-South-
 ern hornworm:
left carefully alone, as the caterpillars will sure- Pupa. Naural
ly die, leaving the parasites to hatch out. If Fa xp.
 Sta. uL 48.)