F. C. Bishopp.
The Distribution of the Nose Fly and Other Species of Gastrophilus in the United States.
Psyche 24(6):182-187, 1917.

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18% P3yche December
another queen leave the entrance with a similar burden. This
led me to examine some twenty nests-all, in fact, that I had time to excavate before 1 was obliged to proceed with the party. My rather hurried observations showed that about half of the craters had been established by single queens but that the others were each the work of two cotiperating queens. One crater actually contained five queens, four dealated and one with intact wings! It appears, therefore, that about 50 per cent. of the colonies of mimicus are pleometrotic in origin. That they probably remain so is indicated by the fact that on fornier excursions in Arizona I have on several occasions taken more than one dealated queen from a single adult colony of this ant.
The foregoing observation is of interest to the myrmecologist, because the mimicus queens were actively cotiperating in the con- struction of a single nest as if they had been so many workers, whereas in the rare cases of Lasius jlavus and brevicornis above cited the consociation of two queens may be interpreted as due to an accidental meeting under the same stone just after the marriage flight. Of course, it is very probable that in all the cases the queens in the same nest were sisters that had met after fecunda- tion, since queens from different maternal nests would hardly work together so harmoniously. Nevertheless, the'very high percentage of cases of primary pleometrosis in mimicus points to the existence in this ant of a pronounced tendency for recently fecundated sisters to assemble in pairs or even greater numbers for the purpose of founding and developing a colony in common. THE DISTRIBUTION OF THE NOSE FLY AND OTHER SPECIES OF GASTROPHILUS IN THE UNITED
STATESal
BY F. C. BISHOPP,
Bureau of Entomology, Dallas, Texas.
The distribution of the species of bot flies in the United States is a question which has been much neglected. Each is of consid-
erable importance to stock raisers and farmers in this country and 1 Published by permiasion of the Chief of the Bureau of Entomology.



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lH7] Bishopp-Nose Fly and other Species of Gmtrophilus 1 83 it seems strange that more facts regarding their introduction, spread and local and seasonal abundance have not been recorded. The common horse bot or nit fly, Gastrophilus intestinalis De Geer, on account of its abundance and comparatively slow flight, has been most readily observed and most frequently mentioned in literature. It was undoubtedly introduced into this country many years ago and has become widely spread throughout the United States. We have records <of its occurrence in nearly all Fig. 1. Map showing the distribution of the nose fly, Gasirophilus h~mor- rhoiddis L. in the United States. The large dots indicate localities where this insect has been reported and the small dots its probable distribution. parts of the country though it seems to vary much in local abundance. At high elevations it seems to be rare. The chin fly, G. nasalis L., also appears to be well distributed over the United States. We have rather clear records of its oc- currence in practically all states from Texas to North Dakota and from New York to California; also in the western part of Canada. It occurs, no doubt, in the eastern part of Canada, and in the eastern states of the Union.
The nose fly, G. h~morrhoidalis L., is undoubtedly the most im- portant economic species of the three when it is present in abun-



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184 Psyche [December
dance, due to the worriment caused by the adult during the period of oviposition.
The distribution of the nose fly was less known than the others until the work of the Bureau of Entomology on this pest was taken up three years ago. The common name which is generally used over the territory where it abounds and the scientific name of one of the other species (G. nasalis) has led to some confusion. It may be said that neither of these names are very appropriate as the eggs of G. ha?morrhoidalis are laid on the lips and those of G. nasalis under the jaws. The last named species has received the vernacular names of "chin fly" or "throat bot fly." The em- ployment of the common name ''n0s.e fly" for the former species seems to be justified by usage among farmers and the name "throat bot fly" is preferred for the latter on account of the egg-laying habits of the female and the habit of the larvze of this species of attaching occasionally at least in the cesophagus. The early history of the occurrence of this species in the United States seems to be clouded. Lugger, in his second Minnesota Report (p. %I&), records it positively from that state. The actual specimen upon which the statement is based is not in existence? however, according to Prof. C. W. Howard. Some seem to have accredited the species to Kentucky, based on Professor Garman's statements in the Kentucky Experiment Station Report of 1894, but he does not record the species from that state, and informs me he has never seen the fly there.
During the summer of 1914 the writer made preliminary in- quiry into the distribution, history of spread, and the injuriousness of the nose fly in the north-central states, where it had been re- ported to the Bureau as a serious pest of horses. At that time the insect appeared to exist throughout the greater part of North and '
South Dakota, eastern Montana, and possibly to occur in limited numbers in western Minnesota. No effort was made to determine the exact limits of distribution. It is evidenty however, that the species has been spreading southward and eastward, as shown by statements of numerous farmers more recently interrogated in dif- ferent sections. While there is some disparity the statements agreed remarkably well as to the time of first appearance in a given community. In 1914 it appeared that the fly had become es- tablished south of the center of South Dakota only within the



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19171 Bishopp-Nose Fly and other Species of Gastrophilus 185 preceding four or five years. In working northward and west- ward the dates set by farmers as the time of first appearance became earlier until Minot, N. D., was reached where a rather authoritative record was secured of the occurrence of the fly eighteen years before (1896).
During the spring of 1915 and 1916 Mr. W. E. Dove and the writer made further inquiry into the distribution of this insect in parts of South Dakota and Minnesota, and Mr. Dove was located in this region and made further inquiry regarding the history of the spread of the insect during the summers of 1915 and 1916. His work largely substantiated the earlier findings* To supplement personal ~bservations and questioning, a large number of letters of inquiry were sent to farmers and horse breeders in the region from Indiana to Washington, and Kansas to Can- ada. About 350 replies were received. One correspondent each in Colorado, Idaho, Utah and Oregon, and three in Washing- ton replied that the nose fly is present, but there is reason to be- lieve they were mistaken in the identity of the insect, except pos- sibly two in eastern Washingt0n.l All reports from Indiana, Kansas and Missouri were negative. Three affirmative ones were received from Illinois and two from Wisconsin.l While neither was corroborated with specimens it is practically certain that infestations, possibly more or less local, occur in these states. Montana and North and South Dakota are generally infested at this time and central western Minnesota, northern Nebraska and northeast Wyoming undoubtedly so. It appears from replies and personal examinations that the insect is more or less scattered over Iowa, but probably not numerous except in the northwest part. In Canada we have learned through correspondents of the pres- ence of the nose fly in southern Manitoba and saskatchewan. A very interesting discussion regarding the occurrence of the nose fly in Canada appeared in the Proceedings of the Entomologi- cal Society of Ontario for 1915. Professor Lochhead there pre- ,
sents extracts from some correspondence from men in western Canada.
It is my opinion that these correspondents, except one from Ontario, refer especially to G. h~rnorrhoidalis although one sent in specimens of G. nasalis, which is much more easily caught. lyince this article was submitted for publication the localities in Wisconsin and Washington have beenvisited. The nose fly is well established in western Wisconsin but its presence b central Wisconsin and eastern Washington could not be verified.



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186 Psgche [December
This apparently led to some confusion as to the species concerned and the use of the term "nose flyy' led to further confusion. It should be remembered that this vernacular name is applied with few exceptions to G. hcemorrhoidalis by horse breeders and farmers. These men write of the presence of the insect in Alberta as well as Manitoba and Saskatchewan, and it probably occurs still farther west.
The dates of first appearance in the different sections as reported by correspondents agree quite well with what has been found by inquiry by Mr. Dove and the writer. The earliest date given was 1883, by a correspondent in western North Dakota, and a cor- respondent in central Montana (Fergus County) states that they were there in 1898, and another slightly farther west jn Montana gives 1890 as the date of appearance. Wyoming and Minnesota seem to have been invaded during the last seven years, Nebraska within the past six years, Iowa about five years ago, and the other states more recently.
Just why G. h~rnorrhoidalis did not come into prominence as a pest of horses years ago it is difficult to tell. It seems almost cer- tain that the species was brought into this country at an early date with shipments of horses from Europe. Failure to establish itself may have been due to conditions surrounding the imported animals after arrival here; such as adverse climatic conditions. It is possible that climate may have a marked influence on the perpetuation of the species in any region and that it will not thrive in the more humid area east of the present area of great abundance in the Dakotas. It is also barely possible that the species may have been present in parts of this country years ago and then be- came extinct or nearly so, but this is hardly plausible. Certainly our investigations indicate a comparatively recent establishment of the insect in the United States, and that the point of first es- tablishment was in western North Dakota or eastern Montanay or possibly in southern Saskatchewan.
The habits of the insect indicate that its dissemination is largely brought about by the movement o! horses. The long time which the larv~ spend within the host and the rather extended period during which they normally leave the animal add to the danger of spread by shipping or driving horses from infested to uninfested territory. The great number of horses recently shipped from in-



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