DIPTEUA. 
115 
hatched comes out, with two diverging horns, which 
prevents its total immersion in the dung. Hundreds 
of these eggs may be seen in a summer’s days in cow- 
dung, looking like little white specs. The French 
Naturalist compared them to a parcel of cloves stuck 
into a pudding ! When the larvse are ready for hatching 
the egg case opens at the upper end and the young 
maggot escapes. The genus Scatophaga contains several 
species; besides excremental food they prey also on 
other two-winged insects. 
On Plate IV., Fig. 3, is a magnified figure of Tephritis 
(Try pet d) Heraclei, another insect of the family of 
Muscidw. The insects of this group are lively flies, 
and may be not unfrequently seen fluttering over 
leaves in the hot sunshine, and vibrating their prettily- 
spotted wings, which are carried erect, like those of 
butterflies. The species figured lays her eggs within 
the cuticle of celery and parsnip leaves, there they 
hatch and produce little transparent maggots, causing 
large blisters upon them. All growers of carrots are 
aware how often the roots are pierced with many holes, 
which contain small maggots, producing the disease 
called rust; the little creatures’ tails may often be 
seen protruding ; the enemy that hath done this is one 
of the Muscidre, viz., the Psila Posce (Fig. 2), a name 
given to the insect by Fabricius, who probably first 
found it sunning itself on rose trees; Psila dauci 
would be a more suitable name. The insect is not more 
than three lines long. Curtis recommends, as a great 
security against the attacks of these insects, a dressing 
of spirits of tar and sand, to be put on the ground 
before sowing the carrots; the scent of the spirits of 
i 2 
