232 



JOURNAL OF HORTIOULTUBE AND OOTTAQE GABDENEB. 



[ September 10. 1874. 



be reckoned among those they are friendly to horticulture, as 

 its staple food is other caterpillars. 



Two communications have recently been made to the "En- 

 tomologist" on the subject of the colonisation of glow-worms, 

 for it has been thought by some persons that, seeing the species 

 is Tery destructive to snails, it would be a valuable insect in 

 the garden dujing its stage of growth, and also, when developed 

 into the perfect condition, form an object of interest and amuse- 

 ment on the bank or lawn. This species, properly no worm, but 

 ft beetle, and bearing the scientific name of Lampyris noctiluca, 

 the generic appellation from the Greek signifying " shining tail," 

 and the Latin we may freely translate into " night-illuminator," 

 is known in many of our southern counties, yet is rather 

 rare in the north of England I believe. Seen by the hedgesides, 

 and sometimes in wood-openings during the summer months, 

 the glow-worm has often excited the enthusiasm of the stroller 

 in the country, and led him to perpetrate some effusion in prose 

 or verse, with the usual redundancy of adjectives and unmean- 

 ing epithets. It has certainly also inspired nobler minds with 

 ideas, such as Cowper, Gilbert White, and Johnson ; and though 

 there are occasional instances of luminosity in other species of 

 the beetle tribe, 

 and in centipedes 

 (and the eyes of 

 many moths are 

 lustrous after 

 dusk), the glow- 

 worm is the only 

 British insect that 

 is a light-producer, 

 and reported to be 

 so in all stages of 

 its development. I 

 say reported, be- 

 cause as yet I am 

 hardly prepared 

 to give credence to 

 the assertion that 

 the eggs are lumi- 

 nous, though there 

 cannot be a doubt 

 that the larva^ ex- 

 hibit , possibly 

 throughout their 

 life, a pale light, 

 which is more like 

 that emitted by 

 the male beetle 

 than the steady 

 brilliant light cf 

 the female and 

 ■winpleES insect — 

 steady at all event? 

 60 long as the in- 

 sect wills, for it is 



able to suppress it at pleasure, much to the astonishment of 

 the rustic lad, who, eager to pickup this " star of earth," seeks 

 in vain for it in the grass after it has withdrawn its light in 

 alarm. And this power is not one of the least remarkable 

 circumstances in glow-worm history. 



There has been almost as much discussion as to the nature 

 of the glow-worm's light as about its intent. Philosophers 

 are divided as to whether it is caused by a kind of slow com- 

 bustion, by phosphorescence, or by some other chemical de- 

 composition which produces light in the same way as does the 

 slow oxidation of phosphorus. Introducing it into oxygen 

 gas, gives increased brilliancy; and Dr. Todd, who went in for 

 several glow-worm experiments in 1824, found that when re- 

 moved from the insect, the organ continued to shine for awhile, 

 and when the light was apparently quite extinguished, heat, 

 friction, electricity, or the application of either camphor, 

 ammonia, or alcohol, provoked it to show itself again. I 

 think, on consideration, we shall agreo that there is force in 

 Mr. Newman's remark when he writes, " The universally 

 received hypothesis that the light of the female glow-worm — 

 like a chignon, a pannier, or a crinoline amongst ourselves — 

 is a lure to attract the male, requires investigation." The 

 luminosity in a degree in the larvae, pupa;, and males, tells 

 against this notion. Another well-known entomologist, Mr. 

 Wood, expresses the like doubt, and grants that it is unfor- 

 tunate to have to disturb so poetical a theory. He adds, "I 

 believe that the phosphorescence was given to it for the same 



reason that the butterfly's wing glows with many-coloured 

 plumage, and the Rose is dowered with softly-tinted petals 

 and sweet perfume." 



Glow-worms are seen during the summer months. A popular 

 belief associates them with the season when the nightingales 

 are in full song. They are not often noticed in August, and 

 quite exceptionally in September. The females (true beetles, 

 though 60 dissimilar to their partners) are flat soft-bodied 

 creatures, black-in colour, and with a few pale spots along the 

 sides of the segments. The legs and antenna; are short; and, 

 taking it altogether, we are not astonished it has been sup- 

 posed to be a larva or grub. A close investigation proves that 

 the light proceeds from the hinder segments, and observers 

 have variously described it as white or greenish. Those who 

 visit woods at the evening hour report that they have often 

 met with or captured male glow-worms, though they are fre- 

 quently lacking in collections of our native beetles. Like the 

 females, they are soft-bodied, but have the legs and antenna; 

 more developed, and the usual wings and elytra or wing-cases. 

 The light in these insects is confined to the head, and exists 

 there as two small spots merely, that it has not much bril- 

 liancy. One judges 

 from the denial in 

 some quarters that 

 there is any lumi- 

 nosity in the male 

 glow-worms ; but 

 the evidence is 

 sufficient to my 

 thinking, though I 

 regret I have not 

 personal acquaint- 

 ance with the in- 

 sect. The eggs, 

 according to Mr. 

 Newman's obser- 

 vations, are drop- 

 ped casually by the 

 beetle, without any 

 regard as to the 

 oliject on which 

 they may rest, and 

 to which they ad- 

 hero by a gummy 

 secretion. No 

 sooner do the 

 young larva; 

 emerge than they 

 begin to eat ; their 

 food throughout 

 their existence in 

 that state being 

 the land molluscs, 

 especially of the 

 genus Zonites, 

 though both the shelled and shell-less types are attacked, and 

 it is conjectured that when not feeding the larva conceals 

 itself in the sheUs of snails, which would account for the in- 

 frequenoy of its discovery by naturalists. It also devours the 

 eggs of snails — a valuable piece of service. Several descriptions 

 have been given of a carious telescopic apparatus with which 

 the extremity of the boJy of the glow-worm larva is provided, 

 and which, when it is pushed out by the larva, expands at the 

 end into a little brush. This is employed as a help in loco- 

 motion — a sort of extra leg — and also as a cleaning appliance, 

 to remove deposits of slime and dirt that may have got upon 

 the body, and that cannot be otherwise reached. We do not 

 positively know how long the larval life lasts, but as beetle 

 larva; are generally of slow growth, it is likely these are hatched 

 the year preceding, as they enter the pupal state in April. 



At present, then, the glow-worm is only prospectively a 

 garden insect. Could the species be introduced commonly it 

 might claim to be both beautiful and useful ; for not only the 

 larva;, but the females are devourers of molluscs; the males, 

 as is thought, are flower-lovers. AH that has been done yet 

 has been the transfer of females from the open ground to the 

 garden lawn, and the light has been seen for a number of 

 nights subsequently, getting paler till it died out; but no larva; ' 

 or beetles have followed these in the next season, showing that 

 it eggs were deposited they had failed to continue the race in 

 that spot. The best way would be to get a good number of 

 larvae, could that be done, or else the eggs, and place these in 



71. — ilET.4M0RriI()SES OF THE GLOW-WORM. 



