15« 



DIVISION OF ENTOMOLOGY. 



Fig. 1. 



Fiff. 2. 



'f3 



The American Frit Fly [Oscinis variabilis, Loew.) 



Attack. — 1. A small yellowisb-white, legless maggot, which may be found in 

 autumn, de.stroj'ing the bases of the stems of several kinds of grasses and fall- 

 wheat, 



2. Also occurring in spring-wheat and grasses in June, attacking the young 

 root-shoots close to the ground, and either destroying or seriously weakening them. 



For the last three years a small Oscinid fly has been bred from the roots 

 of various grasses, to some species of which the injuries had been considerable. 

 Agropyrum caninum^ A. teneruiii and A. repens (Couch grass) suifered severely. Two 

 forms of Poa pratensis, from the North- West Territories, and Elymus Canadensis, were 

 also badly attacked. 



Dining the past summer spring-wheat has been seriously injured in several 

 places in the neighbourhood of Ottawa, and specimens of infested spring 

 wheat, sown on 19th April, were sent to me in June, containing not only the pupae or 

 chrysalis cases of this fly, but also those of the Hessian Fly (Cecidomyia destructor, 

 Say), and the Wheat-stem Maggot (Meromyza Americana, Fitch). 



These specimens, which were forwarded by Mr. Freeman Britton, ofGananoque, 

 Ont., were of particuhii- interest. From them were reared the Hessian Fly and 

 American Fi-it Fly at the end of June, and a few weeks later the fly of the Wheat- 

 stem Maggot appeared. Thus it was proved that all of these insects attack spring- 

 wheat in the stools or root-shoots in the same way as the}^ are known to attack 

 autumn-sown grain. In my last report I drew attention to the fact that the Wheat- 

 stem Maggot attacked certain grasses in this manner; but it is now shown by the 

 above that there is in this disti-ict a brood of each of the three above-mentioned 

 pests, which appears in the beginning of May, and that the eggs are laid on the root- 

 shoots of young growing grain. I am not aware that this fact has been previously 

 noted. Later in the season abundant evidence was found as to the extent of this 

 injury. At Eastman's Springs a field of spring-wheat was observed, the yield of which 

 had certuinlj^ been reduced 75 per cent. In hardly any part of the field could a 

 plant be found with more than one stem, and this was weak and spindly, with the 

 ear fi-equcntly only half filled with grain. Upon examining the I'oots it could 

 plainly be seen that the siools had formed, but had been subsequently destroyed by 

 hosts of larvas of the above insects. The dead i^lants in the di-ills also showed that 

 man}' more plants had been killed than there were growing in the field. Of the 

 insects occurring in the injured plants, the American Frit Fly was by far the most 

 abundant. 



The three insects are easily distinguishable in all their stages. In the larval or 

 maggot stage, in which they do all their injury to crops, they may be known by the 

 following characters. 

 1. The American Frit Fly. — The maggot is long and slender, of a yellowish-white 



colour, and has two small but distinct black hook-like jaws. The last division of 



the body bears two little knob-like processes. Length when full-grown, about 



■j^2 of an inch. 



