REPORT OF THE ENTOMOLOGIST. 



385 



The egg, as found in the ovaries, may be described as follows : Color 

 white. Form gourd-shaped, the globular part measuring 0.21 mm in 

 length and O.U mm broad; the stem 0.35 mm long and 0.04 mnl broad, the 

 entire length being O.50 u,m . 



This was the last wingless female I was able to secure, although the 

 search was continued during the entire month. On May 28 two of the 

 potted wheat-plants were examined, and to my surprise each contained 

 a two-thirds-grown larva in the space below the upper internode. A 

 careful search failed to reveal any larvae that could have emanated from 

 the eggs deposited in the plants two weeks previous. 



On the 1st of June, however, I found a minute larva on the inside of 

 the single potted plant examined. 



As it became necessary for me to leave Illinois at once and locate 

 elsewhere, all observations in this field were necessarily put at an end. 

 The remainder of my potted plants were taken with me, and on reach- 

 ing my destination were placed in a newly-constructed breeding cage. 



From one of these plants, on June 7, 1 took a small larva, and on the 

 20th a wingless female appeared in the cage, and on the 23d I took a 

 second adult from another plant. This last was also a female, but with 

 aborted wings, and had died before making her way out of the straw. 



It seems hardly j)robable that either of these adults or the larva? 

 found in the plants on May 28 could have developed from eggs depos- 

 ited by females which had passed the previous winter in last year's 

 stubble or straw, as the spring of the present year was cold and back- 

 ward. It is more probable that they wintered in the new wheat as larva3, 

 the eggs having been deposited the previous autumn, which was excep- 

 tionally mild until quite late in the season, thereby maturing females 

 which would otherwise have passed the winter as pupae. Since coming 

 to Indiana, the 4th of June, but two adults of the common form have 

 come under my observation. One of these was captured in a field of 

 timothy on June 12. The other was bred July 21 from wheat straw re- 

 moved from the field on the 18th. Both of these possessed well devel- 

 oped wings. 



In all fields of wheat or rye examined in the vicinity of Blooming! on 

 and Normal, III., I found in considerable numbers a form of Isosoma 

 much larger, possessing fully developed wings, and in several minor 

 features differing from the common form of tritici.* 



On May 29, while searching for larvae in growing wheat in the field 

 from which my potted plants were taken, I noticed a plant the upper 

 and younger leaves of which were dead and discolored, as if some in- 

 sect had been at work in the upper r)ortiou of the stem. 



On examination I found just below the affected part a pupa, which 

 unquestionably belonged to this larger form of Isosoma. There was, 

 moreover, ample proof that the larva had previously inhabited the 

 same quarters. 



On the 3 1st I noticed that one of my potted plants began to show 

 some peculiarities of growth, while there was no indication of forming 

 any head. There was an abnormal gall-like development of the sheath 

 where the head should have appeared. On opening this a larva, much 

 too large to belong to the ordinary form of tritici, was found within, 

 having evidently subsisted in and about the upper joint. 



I visited the field again before leaving for Indiana, but could obtain 

 no additional larvae or pupae, and my potted plants taken with me con- 

 tained none. 



* This is the species described as Isosoma grande in a previous part of this re- 

 port (p. 358).— C. V. R. 



25 A-^->84 



