Marco teórico referencial

semi-permanent waters are created principally by irrigation water, a factor peculiar to the region and not present in other sections of the country where practically all studies of mosquito biology have been made. Mosquito breeding waters of this type are practically free from

CORRELATION OF DATA 9 3 natural enemies of mosquito larvae, containing only a few forms that can quickly establish themselves when water is present. Naturally, fish shown to be the most destructive enemy of mosquito larvae in Utah cannot survice in these semi-permanent waters. In these waters, successive broods of mosquito larvae complete development through­ out the season and the mosquitoes maturing in these semi-permanent pools are species that produce several generations a year. All of these above mentioned agencies contributing to the prolific reproduction of mosquitoes in semi-permanent waters of Utah have been previously evaluated independently under major headings in this paper and their primary importance established. It is significant that irrigation water is the most important breeding water throughout the season, when compared to breedng waters from other sources. This has been con­ clusively shown in a typical section in the vicinity of Salt Lake City. It has been consistently demonstrated in this area that fish constitute the most important natural enemies of mosquito larvae, and where fish are well established in bodies of water that retain a constant level, mosquito larvae rarely complete development. It is further significant

that Aedes dorsalis, the most abundant and dominant species of mos­

quito in Utah throughout the season, is a plains type; it reproduces most abundantly throughout the year in agricultural sections where ir­ rigation is common, and produces many generations during a season.

Thus, Aede dorsalis is admirably suited to this semi-arid region where

irrigation is present, reproducing in great numbers in these semi-per­ manent waters free from natural enemies. This combination of factors in Utah insures, under present conditions, the continued prevalence and excessive abundance of adult mosquitoes in the agricultural sec­ tions throughout the entire mosquito breeding season.

9 4 THE MOSQUITOES OP UTAH

Pl a t e X I I I Male Hypopygia:

25. Aedes campestris 27. Aedes vexans 29. Culex tarsalis 26. Aedes niphadopsis 28. Anopheles freeborn i 30. Theobaldia inornata

MOSQUITO LARVAE 9 5

Pl a t e XIV

M osquito Larvae: Head and Posterior Segments

THE MOSQUITOES OF UTAH 39 Pl a t e X V Mosquito Larvae 37, 38. Aedes fitchii 39, 40. Aedes niphadopsis Aedes pullatus Aedes punctor

MOSQUITO LARVAE 49 Mosquito Larvae: Aedes stimulans Aedes vexans Culex tarsalis Theobaldia inornata

9 8 THE MOSQUITOES OF UTAH Dyar, H. G. and Knab, F. 1918 Dyar, H. G. 1922 Dyar, H. G. 1928 Edwards, F. W . 1932 Freeborn, S. B. 1926 Harris-Hamlyn, R. 1933 Headlee, T. J. 1921 Hearle, E. 1926 REFERENCES CITED

Aedes niphadopsis, Ins. Ins. Mens. Vol. V, p. 166.

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Diptera, Fam. Culicidae, Genera Insectorum. P. Wytsman, Brussels, fasc. 194, p. 258. The Mosquitoes of California, Univ. of Calif. Agri. Exp. Sta. Vol. 3, No. 5, pp. 333-460.

Some Ecological Factors Involved in the Dispersal of Mosquitoes in Queensland, Reprints from Bull, of Entom ological Research, Vol. XXIV. Part 2, July, 1933.

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Howard, L. O., Dyar, H. G. and Knab, F.

1912 to 1917

The Mosquitoes of North and Central America and the W est Indies, Carnegie Inst, of Wash. Pub. 159, Vols. 1-4.

King, W . V ., Bradley, G. H. The Mosquitoes of the Southeastern States, U. S. and McNeel, T. E. 1939 Knowlton, G. F. and Rowe, J. A. 1935 Komp, W . H. W . 1923 (Revised 1941) Mail, G. Allen 1934

Dept, of Agri. Mis. Pub. No. 336.

Notes on Utah Mosquitoes, Contributed from the Dept, of Entom ology, Utah Agri. Exp. Sta. Pub­ lication authorized by Director, May 1, 1935.

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Matheson, Robert 1929

A Hand Book of the Mosquitoes of North Amer­ ica, Publisher C. C. Thomas, Springfield, 111., a n d

REFERENCES CITED 9 9 New Jersey Mosquito New Jersey Mosquito Extermination Association,

Extermination Association Proceedings of the Annual Meetings.

1923 to 1942 Owen, W . B. 1937 Purdy, William C. 1925 Rees, Don M. 1934 Rees, Don M. 1935 Rees, Don M. 1939 Rees, Don M. 1941 Rees, Don M. 1942 Rudolfs, W . 1923

Salt Lake City Mosquito Abatement District 1929 to 1941 Theobald, F. V. 1901 to 1910 Wesenburg-Lund, C. 1920

The Mosquitoes of Minnesota, with Special Refer­ ence to Their Biologies, Univ. of Minnesota Agri. Exp. Sta. Tech. Bull. 126.

Biological Investigation of California Rice Fields and Attendant Waters, with Reference to Mos­ quito Breedings, U. S. Public Health Service Bull. No. 45.

M osquito Records from Utah, Pan-Pacific Ento­ mologist, October, 1934, Vol. 10, No. 4, pp. 161­ 165.

Observations on a M osquito Flight in Salt Lake City, Bull, of the Univ. of Utah, Vol. 25, No. 5, Feb. 1935, pp. 1-6.

Origin of M osquito Producing W aters in the V i­ cinity of Salt Lake City, Utah, Bull, of the Univ. of Utah, Vol. 29, No. 5, Feb. 1939, pp. 1-14. An Informative Bulletin on Mosquito Abatement in Salt Lake City, Bull, of the Salt Lake City Mosquito Abatement Dist., April, 1941, pp. 1-34. Supplementary List of Mosquito Records from Utah, Pan-Pacific Entomologist, April, 1942, Vol. XVIII, No. 2, pp. 77-82.

Observations on the Relations Between A tm os­ pheric Conditions and the Behavior of Mosquitoes, N. J. Agri. Exp. Sta., New Brun., N. J., Bull. 388. Survey of the Mosquitoes of Salt Lake City. Salt Lake City Mosquito Abatement District, Reports 1929-1941.

A Monograph of the Culicidae o f the W orld. Vols. 1 to 5, British Mus. of Nat. Hist., London.

Contribution to the Biology of Danish Culicidae. Mem. Acad. R. Sci. and Letters, Copenhagen, Sec. Sci. Pt. 8 Ser. 7.