ENTOMOLOGICAL SOCIETY. 



77 



The Hessian Ely (Fig. 42 — greatly magnified) is probably 

 more prevalent than it is generally thought ; but as its depredations 

 in most places are not serious they are not observed. The injuries 

 to fall wheat in the autumn are greater than by the more con- 

 spicuous attack on the stem during the summer by the spring 

 brood. Occasionally the spring brood attacks the wheat plants in 

 the succulent root shoots just as is done by the autumn brood ; this 

 would be due I think to a late spring holding back the development 

 of the wheat plants, The eggs would be laid on the leaves, and the 

 young maggots might attack the shoots too severely to allow of 

 them developing into stems. It has been frequently noticed that 

 insects are not belated to the same extent as plants by cool spring 

 Fig. 42. weather, 



The Wheat Joint- worm (Isosoma tritici, Fitch). (Fig. 43 — the fly highly magni- 

 fied). In 1895 specimens of injured wheat straws bearing many galls in the bases of the 

 sheathing leaves of the stems were sent from Meaford, on the Georgian Bay, by Mr. 

 Thomas Harris ; these were considered to be Isosoma hordei, Harris. The injury to the 

 infested crop amounted to 5 per cent. 

 There was no recurrence of the attack 

 last year at that place ; but a somewhat 

 similar attack upon wheat appeared at 

 Verdun, Bruce Co., on the opposite side 

 of the peninsula. Many specimens were 

 sent to me by Mr. William Welsh, both 

 in the autumn of 1897 and last spring. 

 The galls were different from the Meaford 

 specimens in that there was little swell- 

 ing, and the cells of the larvse were 

 almost entirely in the tissues of the stem 

 proper, short sections of which were 

 rendered hard, woody, and brittle by the 

 operations of the insects. From some 

 of these stems a large number of the 

 flies were reared. These have been identified by Dr. L. O. Howard and prove to be 

 Isosoma tritici of Fitch. The injury was serious, attacked stems producing fewer and 

 smaller grains than the others. From the Verdun material, in addition to the gall 

 makers, two kinds of parasites were reared, Homoporus chalcidiphagus, Walsh, and 

 Eupelmus epicaste, Walsh ; but these were not present in sufficient numbers to affect 

 the outbreak to any appreciable degree. During the past summer loss from this Joint- 

 worm was not so great as in 1897, so it is to be hoped that its natural enemies may 

 have increased. The eggs of the joint-worms are inserted into the young green straws 

 in June by the female flies. Wheat, oats, rye and barley are damaged. There is 

 only one brood in the year, a few of the flies issuing in the autumn, but most of 

 them not till the following spring. Most of the galls are situated in the first or 

 second joints of the stem above the root, and, as the normal time of emergence is in 

 the spring, any treatment of the stubble such as burning over or ploughing down 

 deeply, by which the insects are destroyed or smothered, must reduce their numbers 

 considerably. Mr. Welsh noticed that many of the hardened portions of the stems 

 were broken from the straw in threshing and were found among the rubbish or in the 

 grain. These pieces from half an inch to one inch in length contain from five to 

 ten larvse. This shows that, besides treating the stubble, these pieces of stem as 

 well as the straw must also be attended to. The broken-off hardened pieces should 

 be collected at threshing and cleaning and burned. Likewise straw from fields where the 

 joint-worms have been found should be destroyed by either feeding or some other means 

 before the time at which the flies should appear. 



The Pea Weevil (Bruchits pisorum, L.). As in previous years many inquiries 

 have come in for the best means to kill the " pea bug " in seed pease. The life-history is 



Fig. 43. 



