THE BEETLE. 



549 



The Cantharis is of the beetle kind, from 

 whence come cantharides, well known in the 

 shops by the name of Spanish flies, and for 

 their use in blisters. They have feelers like 



an English summer seldom yields, when not a breeze 

 disturbs the balmy air, and ' every sense is joy," and 

 hundreds of these radiant worms, studding their mossy 

 couch with mild effulgence, were presented to your won- 

 dering eye in the course of a quarter of a mile you 

 could not help associating with the name of glow-worm 

 the most pleasing recollections. No wonder that an 

 insect, which chiefly exhibits itself on occasions so inter- 

 esting, and whose economy is so remarkable, should have 

 afforded exquisite images and illustrations to those poets 

 who have cultivated natural history. 



If you take one of these glow-worms home with you 

 for examination, you will find that in shape it somewhat 

 resembles a caterpillar, only that it is much more depres- 

 sed ; and you will observe that the light proceeds from 

 a pale-coloured patch that terminates the underside of 

 the abdomen. It is not, however, the larva of an insect, 

 but the perfect female of a winged beetle, from which it 

 is altogether so different, that nothing but actual observa- 

 tion could have inferred the fact of their being the sexes 

 of the same insect. In the course of your inquiries, you 

 will find that sexual differences even more extraordinary 

 exist in the insect world. 



It has been supposed by many that the males of the 

 different species of Lampyris do not possess the property 

 of giving out any light ; but it is now ascertained that 

 this supposition is inaccurate, though their light is much 

 less vivid than that of the female. Ray first pointed out 

 this fact with respect to L. noctiluca. Geoffrey also 

 observed that the male of this species has four small 

 niminous points, two on each of the two last segments of 

 the belly ; and his observation has been recently con. 

 firmed by Muller. This last entomologist, indeed, saw 

 only two shining spots ; but from the insect's having the 

 power of withdrawing them out of sight, so that not the 

 smallest trace of light remains, he thinks it is not impro- 

 bable that at times two other points still smaller may be 

 exhibited, as Geoffroy has described. In the males of 

 L. splendidula and of L. hemiptera the light is very dis- 

 tinct, and may be seen in the former while flying. The 

 females have the same faculty of extinguishing or con- 

 cealing their light a very necessary provision to guard 

 them from the attacks of the nightingale and other noc- 

 turnal birds. Mr White even thinks that they regularly 

 put it out between eleven and twelve every night ; and 

 tney have also the power of rendering it for awhile more 

 vivid than ordinary. 



Authors who have noticed the luminous parts of the 

 common female glow-worm, having usually contented 

 themselves with stating that the light issues from the three 

 last ventral segments of the abdomen. I shall give you 

 the result of some observations I once made upon this 

 subject. One evening, in the beginning of July, meet- 

 ing with two of these insects, I placed them on my hand. 

 At first their light was exceedingly brilliant, so as to 

 appear even at the junctions of the upper or dorsal seg- 

 ments of the abdomen. Soon after I had taken them, 

 one withdrew its light altogether, but the other continued 

 to shine. While it did this, it was laid upon its back, 

 the abdomen forming an angle with the rest of its body, 

 and the last or anal segment being kept in constant mo- 

 tion. This segment was distinguished by two round and 

 very vivid spots of light ; which, in the specimen that 

 had ceased to shine, were the last that disappeared, and 

 they seem to be the first parts that become luminous, 

 when the animal is disposed to yield its light. The pen- 

 ultimate and antepenultimate segments each exhibited a 

 middle transverse band of yellow radiance, terminated 

 towards the trunk by an obtusely-dentated line j a 



bristles, flexible cases to the wings, a breast 

 pretty plain, and the sides of the belly wrinkled. 

 Cantharides differ from each other in their 

 size, shape, and colour ; those used in the 



greener and fainter light being emitted by the rest of 

 the segment. 



Though many of the females of the different species of 

 Lampyris are without wings, and even elytra, (in which 

 circumstance they differ from all other apterous Coleo- 

 ptera,) this is not the case with all. The female of L. 

 Jtalica, a species common in Italy, and which, if we may 

 trust to the accuracy of the account given by Mr Waller 

 in the Philosophical Transactions for 1G84, would seem 

 to have been taken by him in Hertfordshire, is winged ; 

 and when a number of these moving stars are seen to 

 dart through the air in a dark night, nothing can have 

 a more beautiful effect. Dr Smith tells us that the 

 beaus of Italy are accustomed in an evening to adorn 

 the heads of the ladies with these artificial diamonds, by 

 sticking them into their hair ; and a similar custom pre- 

 vails amongst the ladies of India. 



Besides the different species of the genus Lampyris, 

 all of which are probably more or less luminous, another 

 insect of the beetle tribe, Elater noctilucus, is endowed 

 with the same property, and that in a much higher de- 

 gree. This insect, which is an inch long, and about 

 one-third of an inch broad, gives out its principal light 

 from two transparent eye-like tubercles placed upon 

 the thorax ; but there are also two luminous patches con- 

 cealed under the elytra, which are not visible except 

 when the insect is flying, at which time it appears 

 adorned with four brilliant gems of the most beautiful 

 golden-blue lustre ; in fact, the whole body is full of 

 light, which shines out between the abdominal segments 

 when stretched. The light emitted by the two thoracic 

 tubercles alone is so considerable, that the smallest print 

 may be read by moving one of these insects along the 

 lines ; and in the West India Islands, particularly in St 

 Domingo, where they are very common, the natives were 

 formerly accustomed to employ these living lamps, which 

 they called Cucuij, instead of candles in performing their 

 evening household occupations. In travelling at night, 

 they used to tie one to each great toe ; and in fishing and 

 hunting required no other flambeau. Southey has hap- 

 pily introduced this insect in his " Madoc," as furnishing 

 the lamp by which Coatal rescued the British hero from 

 the hands of the Mexican priests. 



" She beckoned and descended, and drew out 

 From underneath her vest a cage, or net 

 It rather might be called, so fine the twigs 

 Which knit it, where, confined, two fire-flies gave 

 Their lustre. By that light did Madoc first 

 Behold the features of his lovely guide.'" 



The brilliant nocturnal spectacle presented by these 

 insects to the inhabitants of the countries where they 

 abound, cannot be better described than in the language 

 of the poet above referred to, who has thus related its first 

 effect upon the British visitors of the New World : 



" Sorrowing' we beheld 



The night come on ; hut soon did night display 

 More wonders than it veil'd : innumerous tribes 

 From the Avood cover swarm'd, and darkness made 

 Their beauties visible : one while they streamed 

 A bright blue radiance upon flowers that closed 

 Their gorgeous colours from the eye of day ; 

 Now motionless and dark, eluded search, 

 Self-shrouded ; and anon, starring the sky, 

 Rose like a shower of fire." 



With regard to the immediate source of the luminous 

 properties of these insects, Mr Macartney, to whom we 

 are indebted for the most recent investigation on the 



