35 



possess the property in their perfect state have it, though, perhaps, in a less degree in 

 their early stages. 



The light-giving Lampyridce are represented in Great Britain by the common Eng- 

 lish glow-worm Lampyris Noctiluca. This species has so often been described that its 

 general characteristics are well known to every one. It is common in the south of 

 England, but is rare in the northern parts, and Scotland. The perfect insect is herbivor- 

 ous, feeding only upon the tender leaves of plants ; but in the larval state they are vora- 

 cious in their habits, devouring snails, slugs and soft-bodied insects. 



It is slightly luminous in its preparatory stages. But the perfect female alone can 

 be said to possess the property to any extent. Indeed it was formerly supposed to 

 be peculiar to this sex, but the male has now been ascertained to give a feeble light. 



Lampyris Italica* though truly a continental species, is taken occasionally in Eng- 

 land, both sexes being luminous. 



Another Coleopterous family, the Elaterida, contains species endowed with the pro- 

 perty of light emitting in a much greater degree than Lampyris. The members of 

 the genus Pyrophorus are natives of the South, and like all " Click-beetles/' are dull 

 sombre-looking creatures, of moderate size. 



Pyrophorus noctilucus is a dark, rusty, brown beetle, about an inch and a half long. 

 A native of the West Indies and Central America. Figure 16 represents this interesting 

 insect both at rest and on the wing. The light chiefly proceeds from the transparent, 



Fig. 16. 



eye-like spots on either side of the thorax. A fainter light is also said to come when the 

 insect is flying from two patches beneath the body, but according to Kirby and Spence 

 this is incorrect. They say : 11 There is a luminous patch in the posterior and inferior 

 region of the metathorax, in a somewhat triangular and depressed cavity, ordinarily 

 concealed by the elytra, but when these are expanded in the act of flying, giving out a 

 more considerable, but more diffused, light than the thoracic reservoirs ; in fact, the 

 whole body is full of light, which shines out between the abdominal segments when 

 stretched, and being strongly reflected by the two basal abdominal segments, gives an 



* General Zoology, Shaw, 1806, Vol. VI., part I, p. 77-78. 



