26 



tenths full-grown naked larva?, and the remaining fifth, in various 

 stages of growth, from half a millimeter upwards. Not unfrequently 

 four or five larv?e were found in a single stalk, and as many as 

 two in probably half those examined. The wheat was about six 

 inches high — the dead stalks from three to five inches. One dark- 

 colored broken puparium noticed contained the larva not yet pupated. 

 In wheat brought iji from the field at this time, eighty-six examples 

 of the fly were found; twenty-two of them larv^B less than half 

 grown and twenty-eight larger, twenty-four recent puparia, mostly 

 formed since collecting, and twelve puparia whose deeper color 

 showed their greater age. On the 5th November the wheat re- 

 maining in this field which had escaped the plow contained many 

 puparia of the fly and an occasional nearly full-grown larva. Tn a 

 strip of young wheat adjoining this (sowed Oct. 5), at this date 

 just beginning to stool, an abundance of larvae of the Hessian fly 

 occurred, — mostly full grown, but a few of them young. As this 

 wheat could not have appeared above ground before October 12, 

 these larvae must have developed from the egg within three weeks. 



I ought to add that careful s^veepings were made both in and 

 around the wheat fields on all our visits, in the vain hope of ob- 

 taining the adult fly. 



The Effingham County Field.— Four sowings were made at 

 Edge wood, as at Billett Station, and at similar intervals; but as 

 only one, that made August 5, was successful, the others failing to 

 germinate on account of the extreme drouth, this one only need be 

 discussed. August 21, this wheat, although well up and large enough 

 to contain the fly, gave us no evidence of its presence. Unfortunately 

 no other visit was made here until September 22, and at this time 

 larva^ of the fly were not uncommon in the fleld,— a few nearly full 

 size, but most of them not over half grown. A number of these were 

 transferred with the wheat to breeding cages, and commenced to 

 form the puparium October 2, and to yield the fly October 22. 

 Combining thete data with those just given for the larva, we have 

 a period of something over forty days for the development of the 

 autumnal generation— the only part of its history not covered 

 by these two observations being the time passed by the full grown 

 larva before the formation of the puparium. This must vary 

 gieatly with circumstances, as the larva ma^ even form its pupa 

 case — if deprived of food - some time before it has reached its 

 normal size. A period of six or seven weeks is i3robably about the 

 normal one for a single generation fully supplied with food, under 

 favorable .weather conditions in fall. Other flies emerged October 29, 

 and proceeded at once to lay eggs in the vial in which the}^ were 

 confine id, the eggs adhering in a string as they were extruded from 

 the ])ody of the female. 



October 12 I found this wheat from six to eight inches high, 

 well stooled, with here and there a dead stalk containing })uparia 

 of the fly, but only rarely a naked larva, — probably in not five per 

 cent, of the instances. Careful sweepings yielded no adults. 



