On Certain Seed-Infesting Chalcis-Flies, 



371 



puncture in the seed coat heals over so that when mature there is no 

 indication as to how the larva came inside the seed. 



As the egg is at first pure white it is very difficult to find in the semi- 

 fluid contents of the unripe seeds. One was found, however, in this 

 position on June 23, 1908, thus proving conclusively that it is in this 

 stage that the insect gains access to the seed. 



The young larva feeds on the soft kernel until September, when it 

 has become full-grown and the kernel of the seed has been entirely 

 devoured. It then becomes proportionally shorter and thicker, pre- 

 paratory to its period of hibernation. The inner seed coat is not injured 

 and surrounds the larva like a kind of delicate cocoon. 



Description of the Insect 



The egg.— One egg found in the kernel of a seed was white, unsculptured 

 and measured .51 mm. long by .15 mm. wide. It is spindle-shaped, 

 pointed at both ends and provided at one end with a long, tail-like 

 process (Fig. 71). 



Larva. — The full-grown larva is grub-like in form with the head 

 drawn under the body. It measures 2.5 to 3.5 millimeters in length, 



Fig. 72. — Apple-seed Chalcis; 

 front view of head of larva 



Fig. 73. — Apple-seed cut open to show full- 

 grown larva of Apple-seed Chalcis within 



depending in large measure on the size of the seed which it inhabits. 

 It is white with brown mandibles and has the head tinged with brown. 

 The mandibles are unarmed, slender and taper to an acute point. The 

 antennae are represented by low tubercles and the face bears on each 

 side a conspicuous group of seven or eight brown tubercles. In their 

 number and arrangement there is a striking variation not only in dif- 

 ferent individuals but almost always in the right and left sides of the 

 same larva (Fig. 72). The body is not clothed with hairs, but is sparsely 



