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simple that beyond the observations of their various attitudes and the way in which they 

 lay their eggs and provide for their young there is not much to be said about them. The 

 sun is the powerful motor for the butterflies, which, during very dark days or during an 

 eclipse, become sluggish and behave as at nightfall. The moths, per contra, are most 

 active during cloudy nights, loving the darkness and avoiding the moonlight. The habits 

 of the caterpillars are varied by the situation in which they are found. Well deserving 

 of close study are the aquatic larvae of Arzama, Sphida among the Noctuidaz and Hydro- 

 campa among the Pyralids, the latter furnished with thread-like gills for water breathing. 

 The enthusiasm with which entomology is pursued when we are young carries with it a 

 success in our observations which is not counterbalanced by the experience that comes 

 with time. Quant 'e bella giovinezza — Lured to be up at five in the morning to catch the 

 moths in their first sleep in the dawn on tree trunks and palings before the birds had 

 disturbed them, finding thus early many freshly disclosed rarities and being amply 

 rewarded for my rising. Caterpillars are also easier found at dawn, before or soon after 

 sunrise. Everything that is beautiful passes with youth, before we have learned to 

 remember, and our experiences are all new and unblunted. 



The necessity of exercising our discriminative faculties makes the study of the habits 

 and structure of these insects a useful one to the mind by enlarging its faculties and, if 

 properly guided, helps one to a kindly philosophy and the enjoyment of unselfish pleasures. 

 But entomology, like every other pursuit, is only the frame upon which our moral char- 

 acter is extended and displayed. 



Most interesting is the study of Variation in the butterflies and moths. We have 

 first to consider the seasonal varieties, where a difference in the different, spring, 

 summer, broods is shown. Then the sexual varieties, peculiar to one sex, as in Ennomos 

 alniaria, where, according to Dr. Packard, we have two kinds of males, etc. Then 

 dimorphic varieties, as for instance Hemaris uniformis, which is, on the authority of 

 Mr. Hulst, apparently a constantly recurring form in both sexes of H. Thysbe. It is not 

 always possible to decide of any two forms which is the variety and which the parent, 

 or original form of the species. The practice of considering the first form that was 

 described as the original form and the latter the variety, is too unscientific to merit 

 consideration. We have then Aberrations, mostly individual in character, in which by 

 suffusion of color, or substitution of one tint for another, also by a change from the 

 normal markings, a departure from the usual form is signalized. The cause of variation 

 is evidently complex. Edwards, Dorfmeister, Weismann, have all shown the influence 

 of cold and temperature in producing varieties. Warmth and light, the geological 

 formation, food-plants, in fact, all the physical environments are, in truth, the factors, 

 but it is not always easy to say which is the determining force. While varieties are 

 considered to be nascent species it is probable that this is only relatively true and that 

 a species may produce, under certain conditions, a variety which has insufficient character 

 to become a species. Light and heat are supposed to produce brighter colours. Natural 

 selection fixes the specific character, hardening it into constancy. The butterflies are 

 gaudier than the moths and most brilliant at the Tropics. The day-flying moths are 

 higher colored, as a rule, than the strictly nocturnal species, which are as dusky as the 

 night during which they range. An objection to this is, that the circumstances under 

 which the caterpillar exists can alone be determining upon the colours of the moth. It 

 is thought that the food-plant influences colour, and that the pigments are made by the 

 chemical processes within the body itself. But the colours of the moth are also directly 

 affected, as I have long shown. I am inclined to believe that the moths are a survival 

 of the oldest form of the Lepidoptera. That their colours are inherited, and that formerly 

 all the Lepidoptera were dusky and active in the night or when, during the whole 

 twenty-four hours, the light was less powerful on the surface of the globe than it is now. 

 The influence of the surroundings of a moth upon its color may be witnessed in the case 

 of Hemileiica tricolor, a pallid, desert-inhabiting form of a black genus of Bombyces. 

 This moth is, as I have shown, a true Hemlleuca, differing only in colour from other 

 species of the genus. I have alluded elsewhere to the method of variation by which the 

 under surface of the wings in the moths which are concealed from the light are the least 

 affected. The fact that the under surface of primaries often corresponds with upper 



