128 



li^JUEIOUS I^fSECTS 



make sure tJiat it has not ali'eady been oviposited in. 

 Head downward, tliey then begin by bending the abdo- 

 men downward, and j^lacing the tip of tbe ovipositor on 

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

 men resumes its natural i^osition, and the ovijDOsitor is 

 gradually worked into the plant to its full extent. 

 With the aid of a good lens, and by j)ulling up the plants 

 on which, they were at work (which, did not apjDear to 

 disconcert them in the least), I could view the whole o'p- 

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

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

 When ja 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, ujDon July third, we examined a large lot of the 

 gi'een 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 fi'om 0.004 to 0.006- 

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



By the beginning of Sej^tember, the infested grain 

 having ripened long before this period, the galls are 

 akeady diy and hard, and the larvae contained in them 

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

 The great majority of these larvse 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 i^erfect 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 TJj)per Canada, thirty- 

 nine galls, on very nearly one-third j)art, were alreadv 

 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, bat 



