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collected in great numbers and fastened to the 

 dress of young people and the trappings of horses, 

 upon which the youngsters would ride through the 

 streets after dark. On such occasions many wanton 

 wild fellows rub their faces with parts of a freshly 

 killed Cucujo "with purpose to meet their neigh- 

 bours with a flaming countenance." 



This Cucujo or Fire-fly is the Pyrofhorus noctiluca. 

 There are a large number of species in the genus 

 Pyrophorus, but they are not all Fire-flies, though 

 probably the majority are more or less luminous. 

 P. noctiluca is the only one whose life-history has 

 been dealt with satisfactorily. As we have said, 

 the perfect insect is very like our Skipjack, but 

 much larger. It measures about an inch and three- 

 quarters in length, and is of a rusty-brown colour. 

 On the hard shield-like crust of the fore body 

 {thorax), there are two oval spots which the older 

 writers thought were the creature's eyes, because 

 they are luminous in the evening. But the chief 

 source of light is on the under side at the junction 

 of the fore body and the hind body, which is not 

 visible except when the beetle is on the wing. 



Like those of the Glow-worm, the eggs of the 

 Cucujo are said to be luminous; and the larva has 

 the same quality. But there is an increase of the 

 light-bearing spots during the larval period. At 

 first the larva has only one luminous area — just 

 behind the head ; but at a later change of skin this 

 is supplemented by a row of luminous points along 

 the sides above the spiracles or breathing-pores. 



