1966] 
Cooper — Eum enine Wasps 
241 
With denticles protruded through the chorion, the larva spasmod- 
ically shortens and thickens its body (for periods of three to five 
seconds), as though forcing itself, by creeping movements, against 
the lateral walls of chorion and the cephalic pole of the egg. These 
exertions drive the denticles, as though saw-teeth, lengthwise through 
the lateral chorion of the medial third of the egg, ever widening the 
two more or less ragged rifts both fore and aft (fig. 3). Following 
each period of rest, lateral pressure, renewed each time that the lar- 
val forebody thickens, tears the rent chorion more widely until, 
finally, the whole anterior half of the egg lies open, cut into dorsal 
and ventral flaps in a fashion that reminds of Wheeler’s (1889) 
description of hatching of the beetle Leptinotarsa decemlineata (Say). 
With its anterior half free of the egg but its hinder body still en- 
closed and adherent within the shriveled chorion, the newly emerged 
larva immediately commences to feed on the nearest prey (fig. 4). 
Though hatched, the larva does not normally quit the chorion until 
it casts its first moult. 
In all, I have watched 16 eggs hatch. The speediest case took 20 
minutes, the longest something less than 90 minutes but more than 
an hour. On the average, with the temperature ranging between 
20°-28°C, hatching requires 45 minutes, with a standard deviation 
of d= 9 minutes. The chorions of most eggs were bilaterally split 
as I have described, but in 3 cases the larva’s denticles penetrated 
one side of the egg only. In each of these instances, the single rent 
was ultimately enlarged by the movements of the larva until the 
whole of its forebody emerged ; these larvae seemed in no way handi- 
capped by failure of the egg to be split on both sides. 
Figures 1-3. — Hatching of the egg of Ancistrocerus antilope (Panz.), 
magnif. 9 X; fig- 1. -unhatched egg; fig. 2. -egg viewed from ventral sur- 
face, ruptor ovi of abdomen have perforated chorion on each side, chorion 
collapsed caudally, mandibular tips of larva visible at cephalic pole 
(below) ; fig.3-egg at mid-hatching seen from the right side, note tear in 
chorion, ruptor ovi of abdomen, and tips of manbibles at lower left. 
Figure 4 — Newly hatched larva in feeding position, magnif. 1 5 X ; the 
larva will normally adhere to the split chorion until instar-2. 
Figures 5-8 — Abdominal ruptor ovi, magnif. 390X ; in each case the 
spiracle to the right (anterior) originates from the segmental tracheal trunk 
of the preceding body segment. Fig. 5. -ruptor of abdominal segment-1, 
nearly profile view. Fig. 6. -ruptor of abdominal segment-1, above. Fig. 
7. -ruptor of abdominal segment-2, in “profile”. Fig. 8. -ruptor of abdominal 
segment-3, in “profile”. 
Figures 9-11 — Spinous sets and laminae (hatched) of the ruptor ovi 
of thoracic segments-1, -2, and -3 respectively, magnif. 500X, see text. 
Note: — Orientation of ruptor ovi in figs. 5-11 is indicated by arrow below 
fig. 9, pointing caudally; all figures are freehand sketches, to scale. 
