which were suitable for use against ants. The results were disappointing and perplexing, no relation being shown between the amount of arsenic present and the results secured by field tests. Whether a mechanical basis can be discovered for the object mentioned remains to be determined.

Leaf cutting bees are the cause of much damage to young fruit trees in southern and eastern Arizona. In the Salt River Valley roses appear to be the only plant subject to injury. Specimens of the species concerned have not been captured by myself or by my correspondents with the exception of a single specimen which reached me in a broken condition.

ENTOMOLOGY AND THE ARIZONA PUBLIC. The foregoing records which purport to be merely a general characterization of the economic insect fauna of Arizona indicate the extent of the field now open for work in that state. While we are still fortunately free, as far as known, from many of the most destructive insect pests of the country, there is no scarcity of native insects with predilections for cultivated crops. The need for entomological protection and entomological investigations is being more and more generally recognized in the state. In 1909 the first appropriation of $3,000 per annum for entomological work was made in the territorial assembly after a hard fight for recognition by the interests most concerned. In 1912, with urgent necessity for economy in all appropriations, the state legislature by a unanimous vote in both houses passed a bill amending the original law and adding $9,000 a year to the original amount. The outlook for future accomplishment in economic entomology in Arizona is most promising and the continued favorable attitude of the public is hopefully anticipated.

PRESIDENT W. D. HUNTER: Two of the most striking entomological observations made on a recent trip in the arid southwest dealt with the house fly and mosquitoes. One would not naturally expect to find an abundance of these insects in such a region. Artificial circumstances tend to overcome natural obstacles in the breeding of these insects. The water used for irrigation allows the mosquitoes to breed in great numbers and carelessness about the disposal of garbage allows great numbers of house flies to be bred.

We will now listen to a paper by Mr. S. J. Hunter on "Apparatus for Maintenance of Thermal Climatic Conditions."

APPARATUS FOR MAINTENANCE OF THERMAL CLIMATIC CONDITIONS

By S. J. HUNTER, Lawrence, Kans.

[A summary of this paper appears in the discussion below.-Ed.]

PRESIDENT W. D. HUNTER: Any discussion?

MR. T. J. HEADLEE: I am very much interested in this subject and should be glad to have the speaker explain the following points: 1st, whether the temperature maintained is supposed to be a constant one, or whether it is intended to show a diurnal variation; 2d, the exact source, nature, measurement or control of the light; 3d, the control of atmospheric moisture.

MR. S. J. HUNTER: This temperature control apparatus (plates 5, 6) is constructed to fulfil our specific requirements. I do not undertake to say that it will fulfil hypothetical conditions arbitrarily imposed. The chamber is 5'x 5'x 8', double glass lined on four sides. The temperature is controlled by an ammonia compressor, while the power is furnished by a 2-H.P. D.C. motor. Sunlight can be admitted from the south and west or excluded as desired, leaving daylight from the north. We can maintain constants or variables from 60° above to 10° below zero F. Standard constant conditions are easier to maintain than the establishment of given curves of variation. Constants do not occur in nature; hence, for the present with these we are not concerned. Standard weather guages keep the records. The purpose of this apparatus is to interpret the influence of temperature and moisture as natural climatic conditions on growth and development. The climatic data is taken from our climatic records, continuously observed since 1868.

MR. T. J. HEADLEE: How does the speaker plan to control or determine the relative proportion of gases in the air?

MR. S. J. HUNTER: Ventilation can readily be secured and normal. conditions of surrounding atmosphere maintained through ventilators aided by electric fans. The moisture content can be controlled by chloride of lime filtration.

MR. T. J. HEADLEE: In the study of the effects of temperature and moisture on the rate of insect metabolism I have not found it possible to control the intensity of the light. The difference in the results obtained from experiments conducted under the same temperature and moisture and under practically the same food and gas conditions at different times of the year are difficult to account for so long as the intensity of the light is an unknown factor. In fact, it is possible that the ascribing of a difference in response obtained

April, '13]

JOURNAL OF ECONOMIC ENTOMOLOGY

Plate 5

STANFORD LIBRA

APPARATUS FOR MAINTENANCE OF THERMAL CLIMATIC CONDITIONS. MAINTAINS NORMAL DOWN TO 10° BELOW ZERO F. UNIVERSITY OF KANSAS, Lawrence, Kansas.