128 INJURIOUS INSECTS 



make sure that it has not already been oviposited in. 

 Head downward, they then begin by bending the abdo- 

 men downward, and placing the tip of the ovipositor on 

 the straw at right angles with the body, when the abdo- 

 men resumes its natural position, and the ovipositor is 

 gradually worked into the plant to its full extent. 

 With the aid of a good lens, and by pulling up the plants 

 on which they were at work (which did not appear to 

 disconcert them in the least), I could view the whole op- 

 eration, which, in some cases, was accomplished in a few 

 minutes, and in others was the work of an hour or two. 

 When a puncture was completed, they usually backed up 

 a little and viewed it for a few seconds, and then appar- 

 ently satisfied, moved to one side and another began." 



Very shortly after this time, the egg must hatch out. 

 For, upon July third, we examined a large lot of the 

 green barley-galls, which had been obligingly forwarded 

 to us by Mr. Pettit, and found the larva of the Joint- 

 worm Fly almost half -grown, that is from 0. 004 to 0. 006- 

 inch long, and about five times as long as wide. 



By the beginning of September, the infested grain 

 having ripened long before this period, the galls are 

 already dry and hard, and the larvae contained in them 

 full grown, measuring now about 0.13-inch in length. 

 The great majority of these larvae are destined to remain 

 in that state, enclosed in their little cells, until the suc- 

 ceeding spring; but as happens with many different in- 

 sects a small percentage of them seem to pass into the 

 pupa, and thence into the perfect state, the same sum- 

 mer that the eggs are deposited. For, out of a lot of 

 one hundred and twenty-four barley-galls, received Sep- 

 tember 10th from Mr. Pettit of Upper Canada, thirty- 

 nine galls, on very nearly one-third part, were already 

 bored with the same kind of small round holes as are 

 made in the succeeding spring by the escaping Joint- 

 worm Flies, some galls containing six such holes, but 



