NO. l8 SENSE ORGANS OF COLEOPTERA — McINDOO 5 



intensity of the illumination. Moore and Cole conducted many tests 

 by confining Japanese beetles in a specially constructed wire-screen 

 cage. Five light intensities were used in securing the reaction time of 

 the beetles. The results obtained are presented in tables and graphi- 

 cally. Their summary is about as follows. Light and tem^Derature 

 above 23° C. are necessary to cause activity in the Japanese beetle. 

 The effect of light as indicated by the rate of locomotor responses 

 was related to light intensity according to Fechner's expression of 

 Weber's law. 



Richmond {6y) devised an apparatus to determine the value of 

 color and intensity of light. Over 100 tests were conducted, using 

 Japanese beetles, but no definite conclusions were drawn from the 

 results obtained. 



Crozier (12) states that when creeping mealworms are tested to 

 light rays, a definite intensity of white light (about 136 m. c.) is re- 

 quired to produce negative orientation away from contact with a ver- 

 tical glass surface. This gives a measure of stereotaxis in terms of 

 phototaxis, or vice versa. The effectiveness of light for the suppres- 

 sion of stereotaxis varies with the wave length. By determining the 

 minimum energy required to inhibit stereotaxis with the different 

 regions of the spectrum, it was found that the maximum effectiveness 

 was sharply localized in the neighborhood of 535 millimicrons. The 

 same author (11) conducted other experiments to show that meal- 

 worms, while creeping, exhibit homostrophic responses and stereo- 

 tropic orientation to lateral contacts. Crozier finally concludes that 

 stereotropism is truly a tiojHC character. 



, (b) i.tgiit traps for beetles 



Artificial light as a control measure was probably first used in 1787 

 for attracting vine moths in luu'ope. Since that date light traps have 

 been gradually developed and improved until today there are many 

 types and varieties of gasoline, kerosene, acetylene, and electric lamps 

 used for this purpose. Most of these have been devised primarily for 

 catching Lepidoptera, but many beetles also are caught in them, and 

 other traps are designed primarily for Coleoptera. It seems that none, 

 however, has given complete satisfaction as a control measure. 



Since 1914 Jarvis and his co-workers (28, 33, 35) have been de- 

 vising light traps to catch sugarcane beetles in Queensland, Australia. 

 Their object has been to develop a trap so simple that it might come 

 into general use in sugarcane-growing regions. A very successful trap 

 has finally been develoj^ed. It consists of a large pan about a yard 

 square, with sides about 4 inches high, and of an ordinary acetylene 



