. Entomology : with special reference to its biological and economic aspects. A, tracks made on paper by a larva of Lncilia carsar moving out of a spot of inkunder the influence of light; a and b show respectively the first and seconddirections of the light. B, tracks made in the dark.—After Pouchet. 3 so ENTOMOLOGY totropic response is either positive or negative according asthe organism moves, respectively, toward or away from thesource of Hglit. Maggots of Lucilia cccsar and of many otherflies are negatively phototropic as a rule (Fig. 289, A), but inthe absence of light ( st
. Entomology : with special reference to its biological and economic aspects. A, tracks made on paper by a larva of Lncilia carsar moving out of a spot of inkunder the influence of light; a and b show respectively the first and seconddirections of the light. B, tracks made in the dark.—After Pouchet. 3 so ENTOMOLOGY totropic response is either positive or negative according asthe organism moves, respectively, toward or away from thesource of Hglit. Maggots of Lucilia cccsar and of many otherflies are negatively phototropic as a rule (Fig. 289, A), but inthe absence of light ( stimuli being excluded, ofcourse) wander about indifferently (Fig. 289, B). Do the different rays of the spectrum differ in phototropicpower? This question has occurred to many investigators,who have found that, in general, the rays of shorter wavelength, as violet or blue, are more effective than those of longerwave length, as yellow or red; the latter in fact acting likedarkness. Ants avoid violet rays as they would avoid directsunlight, but carry on their operations und
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectentomology, bookyear1
