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1915-16.] Structure and Life-History of Bracon sp. 
period of quiescence varies considerably under different conditions, and its 
long duration is a feature of the Braconid’s life-history. In the winter 
it lasts from four to six months, and in summer from three to six weeks. 
The Pupa. 
There is nothing specially noteworthy in the pupa of this Bracon. 
Viewed from the side, the antennae are seen to extend almost the whole 
length of the body. They lie beneath the legs. The thorax is well defined, 
and in its relation to the head gives the pupa a hump-backed appearance. 
The abdomen is distended slightly. In the female the ovipositor is directed 
under the abdomen backwards. The wing-sheaths are very short, scarcely 
extending below the thorax. (Plate I, fig. 8.) 
The Adult. 
Ratzeburg’s * description of Bracon hylobii is as follows 
“ Inner discoidal cell completely closed. N ervus parallelus not interstitial. 
Discoidal cells equally long or nearly so. Metathoracic plates granulate. 
“ B. hylobii. 1^-2 mm. long. Outer and inner discoidal cells equally long. 
Second cubital cell a little longer than the first. Antennae, in the female, 
31-jointed. Ovipositor as long as the abdomen, curved slightly upwards. 
“ All the legs and the greater part of the abdomen reddish-brown ; of the 
latter, in the female, only the middle plate of the first ring, in the male, 
almost the whole of the first ring and the last half of the abdomen, quite 
black. 
“ Thorax and head mostly black, except in the female, where part of the 
metathorax is brown and the margin of the eyes is shimmering. Mouth 
and palps dull brown.” 
My specimens agree generally with this description, except that there 
is a marked discrepancy in size and length between Ratzeburg’s insect 
and mine. The average size in my specimens is 4 to 5 mm., and quite 
a number of females measured as much as 7 mm. Altogether I have 
handled over a thousand specimens, and I have always considered a 3-mm. 
specimen to be a small one. 
Occasionally the black colour which, in Ratzeburg’s description, is 
restricted to the middle plate of the first abdominal segment extends 
to the second and sometimes to the third ring. (Plate I, figs. 1 and 2, 
male and female of Bracon sp.). 
The ovipositor of Bracon consists of two outer sheaths enclosing the 
borer. These sheaths cover the borer for its whole length. They are 
* Ratzeburg, loc. cit. 
