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Writers say that plowing under the stubble does not discommode the 

 joint-worm, and from the fact that this insect is known to appear in 

 great numbers two years in succession in the same field, it is doubtless 

 true of the Wheat-stalk worms. 



It has been ascertained that some insects are more numerous and 

 consequently more troublesome some years than others, and that those 

 years here occur at regularly marked intervals, depending upon the wet- 

 ness and dryness of the seasons. Is this insect subject to the same law ? 

 I think it is, though I am aware I hase that opinion on very small evi- 

 dence. This year has been a dry season, there being scarcely any rain 

 during the months of July and August, and for this reason, and this 

 alone, I think four-fifths of the Wheat-stalk worms either changed to 

 pupae and produced the perfect insects or died. 



Last year the most faithful care and watching of the infested 

 stalks failed to produce any perfect insects ; and I may add here 

 that I have this year failed to get any perfect insects from my first 

 lot of specimens collected, and which have been kept in the shade, 

 though I have now live pupae in that jar, all those I have raised 

 being from specimens later gathered, after they had begun to feel 

 some of the effects of the drought. Last year was more of an ordi- 

 nary year, more favorable for the worms to undergo their trans- 

 formations in their regular manner, for I believe to hatch out in 

 great numbers during July and August is not their normal condition. 



If I am correct in my conjecture, we may not look for very much 

 trouble from that insect next year, nor perhaps for two or three 

 years. If we take the one-fifth that were still larvae August 20th, 

 and deduct from them the number that would be likely to perish 

 after that before pupating, and again the number that must be de- 

 stroyed during the winter, the number left to provide for a brood 

 next season becomes very small. Hence we may safely conclude, I 

 think, that wheat will not be troubled with them next year to any 

 great extent, and I think we have good reason to conclude that, if 

 every seventh year is to be like 1881, the same effects will be pro- 

 duced as have been this year. 



Note.— While the above is going through the press, I take the opportunity to make a 

 correction. Since writing the articls, Isosoma Allynii has been found to be a species ol 

 Eupelmus, another genus of the family C'halcididce. and will be known as E. Allynii. Dur- 

 ing my investigation of the wheat-insect, I obtained from a stalk of a species of wild 

 grass {Eljjmus C'anadensis)a,nother insect, a genuine Isosoma, working on the inside of the 

 stalk in the same manner as the one on the inside of the wheat-straw which I described 

 in the "Canadian Entomologist" for January, 1882, as Isosoma Elymi. I have since ob- 

 tained from my wheat-straws a number of wingless female insects that seem to be the 

 same as the one obtained from the grass, and which were without doubt the authors of 

 the mischief to the wheat. They agree in color except that the wingless specimens are a 

 little lighter where both have pale markings. Both have nine joints to the antennie, 

 these being black except at the base which is pale or brownish. The legs are brownish- 

 ■folack except the joints and feet which are pale, the feet being the lightest. The body is 

 black, the abdomen jet-black, the head and thorax with a brownish tinge with a pale spot 

 on the front part of the thorax above and on the sides, and some pale beneath. They differ 

 some in size. The wingless ones are from. 10 to .11 of an inch long, while the other is only 

 .07 of an inch, but premature development may make the difference. 



The genus Enpehnus is parasitic as far as known, and I presume E. Allynii is no excep- 

 tion. I may say that I have obtained another specimen of this species from a gall in a 

 stalk produced evidently by the regular Joint-worm [Isosoma Hordpi). From this and 

 from the fact that my specimens were obtained from burrows made in the wheat-stalks 

 by this new Isosoma, it seems to me that we have here a parasite on the real Wheat- 

 stalk worm. 



The above new facts make a little less forcible the effect of the dry summer upon the 

 Wheat-stalk worms, though only partially negativing what was said on that subject, for 

 quite a per cent, of the larvse were found dead toward the close ot the drouth, to which no 

 other cause could be attributed than the dry weather. It should be borne in mind also 

 that the Eupelinuiis a probable destroyer of the real wheat enemy: and as far as I can see 

 now the real Wheat-stalk worm is Isosoma Elymi. 



G. H. FEENCH. 

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