DIPTERA. 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 larvae 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 

 {Trypeta) Heradei, another insect of the family of 

 Muscidce. 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 Muscidce, viz., the Psila Mosce (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 



