1914] Melon Fly, Dacus cucurbitae. 181 
its eggs under natural conditions; (2), the external indication 
of egg deposition and (3), the injury caused by the larve. 
Observations were also noted on other host plants injured by 
this fruit fly, but these were not so extensive as those made on 
pumpkin plants. 
1. Ovtposition in stems of pumpkin vines.—-The melon fly 
often deposits its eggs in the stems of cucurbit seedlings. In 
pumpkin vines the eggs are often laid within the tender stems 
near the growing ends (plate X XVII, fig. 3), but the pest is not 
able to puncture the older and tougher stems with its needle-like 
Oovipositor. A gummy substance exudes from the wound and 
hardens in the form of a small, resinous lump on the stems 
(plate X XVII, figs. 1 and 2). 
2. Oviposition in petioles of leaves Occasionally the melon 
fly deposits its eggs within the petioles of the leaves. The 
external indication of oviposition, as in the case of the stems, 
is shown by the resinous material which accumulates at the 
region where the petiole was punctured by the ovipositor. 
3. Ovtposition in pumpkin flowers ——Eggs were found on 
the outer and inner surfaces of the corolla and its lobes (plate 
XXVII, figs.4and7). When the melon fly oviposits on the inner 
surface of a corolla, it punctures the closed flower, glueing the 
eggs either at one end in a mass or scattering them loosely on 
the inner surface of the corolla and its lobes. At that region 
where the flower has been punctured it becomes discolored 
(plate X XIX, figs. 20 and 21). 
Dacus often oviposits within a receptacle formed by its 
ovipositor in the anthers or column of the stamens of the stami- 
nate pumpkin flowers. More often, however, eggs are de- 
posited in the tissue of the cup-shaped disc formed by the 
union of the calyx and corolla, or the eggs are simply dropped 
loosely into this cup-shaped disc. Occasionally, the eggs may 
also be found within the peduncle of the staminate flowers. 
The pest also deposits its eggs in the stigmas and styles 
of the pistillate flowers. The trypetid does not enter the male 
or female pumpkin flowers to lay its eggs, but punctures the 
corolla from the outside with its ovipositor. Wherever the 
ovary of the pistillate flower has been “‘stung’’ by the female 
fly, a resinous material covers the wound (plate XXIX, fig. 
18). Within the ovary, the ovipositor forms a small receptacle 
in which the eggs are laid (plate X XVII, figs. 5 and 8). Eggs 
