REPORT OF THE ENTOMOLOGIST AND BOTANIST. 



237 



collected in patches that would probably c wer half an acre or perhaps more, and there 

 seemed to be a very great number of these patches, so much so that when the wind blew 

 off the bay (Georgian Bay), they would float up the Owen Sound River and collect in 

 any shelter that was open." Mr. Lockerbie suggests that they may have been blown uff 

 the shore by a high wind. 



Judging from a great many letters of correspondents, as well as my own observations, 

 I feel sure that the sudden disappearance of locusts over large districts in Canada was 

 due almost entirely to four kinds of well known parasites — a fungus, intestinal worms, 

 the maggots of two or more species of flies and the locust mite. All of these active 

 friends are well known to entomologists and have been frequently observed before, but, 

 as there has been so much interest evinced in the subject, I give herewith a short account 

 of each, which I feel sure will be acceptable to many. 



Grasshopper Parasites. 



Fungous Disease of Grasshoppers. — A most potent ally in the destruction of locusts 

 when they exceed their normal numbers is a parasitic fungus known by the name of 

 Empusa grylli (Fresenius) Nowakowski. This produces a very infectious disease, tlie 

 efiects of which are frequently observed, but the cause of which is seldom recognized. 

 Diseased locusts were received from Princeton and several other places in Ontario. The 

 disease seems, too, to have been very virulent near Montreal. Mr. T. A. Crane writes 

 from that place, under date of 1st August: "A few days ago the grasshoppers were 

 vigorously attacking my oats. Last evening, when I examined them again, I noticed 

 that they were clinging fast to the tops of the stalks, but they were all dead. Some 

 were minus their heads and some minus their entrails." This describes well the appear- 

 ance of locusts which have succumbed to this disease. 



During the month of August, and later, it was a common thing to see around Ottawa 

 and in almost all other places visited, numbers of different species of locusts, but particu- 

 larly the Two-striped Locust, hanging motionless, generally near the tips of stems of 



grasses and other plants. (Fig. 6.) Upon examining these, 

 they were found to be dead and the bodies frequently dried 

 up, brittle and containing a powdery material. This powder 

 is in reality the spores of a parasitic fungus very nearly 

 allied to the well-known and frequently observed Em])i>sa 

 muscfe, which every year destroj'S so many house flies, leav- 

 ing them de d on windows, curtains, plants, ifec, with a 

 cloud-like deposit of the spores of the fungus around them. 

 Under certain conditions, probably much affected by 

 weather — warm, foggy weather being considered favoural)le 

 — the disease of grasshoppers above mentioned frequently 

 becomes a most fatal epidemic. Each of the mummified 

 bodies is a centre of infection containing myriads of spores, 

 each one of which, blown away by wind or washed down 

 by rain, if it fall upon a locust in a suitable condition, is 

 capable of causing deatli. This useful pax-asite, which d(»ps 

 such efficient service, had attention first drasvn to it by 

 Prof. Herbert Osborn in Iowa, who published his obst^rva- 

 tions, with Prof. Bessey's original description, in Bulletin 

 No. %, Iowa Agr. Coll.. 1884, under the name of Ento- 

 Fig. 6. —Two-striped Locust killed mophthora calopteni. The accompanying original illustra- 

 by fungus. (O. Lugger.) ^^^^^^ kindly loaned by Prof. Otto Lugger, of the University 



of Minnesota, shows a Imirably the attitude of a Two-striped Locust killed by the 

 fungus. 



The Tachina Flies. — Mr. J. E. Richardson, of Princeton, Ont., who, I find from 

 several letters received on this subject, is a close and accurate observer, writes : — 



" July 7. — I have of late noticed, more especially the other day after a rain, flies 

 attacking the locusts. About half a dozen would fly after one, and as soon as it settled 

 down they would alight upon it." 



