106 



THE ORDER OF COLEOPTERA. 



[ Fig- 48. ] most distinctive character is tlie 



extension of the thin thoracic 

 margin, which is narrow in the 

 other sub-families, but is here ex- 

 panded so as, in most cases, to 

 completely cover the head. It is 

 in this sub-family that we find 



Photinus pyealis, Linn.:— Common firefly; or, more ^Up oTippipo rpiTinrlrnhIp fnr flioir 

 properly, Lijrhtning-beetle ; a, larva; f, e, d. head, ^"^ SpCCieS rCmarivaOJC lOr rUCir 



eaUh^enceufrbeX-a"^^^^^ P"!''-^^" "« luminous Or phosphoresccut pro- 



perty, which is possessed by no other insects except a few of the Elate- 

 ridae.* This property is located in one or more of the segments on the 

 under side of the abdomen. The luminous power is intermittent, being 

 exhibited by flashes, and is evidently controlled by the will of the insect. 

 It is a vital phenomenon, and consequently ceases after death ; but the 

 luminous segments can be distinguished in the dried specimen by their 

 uniformly yellow color. 



The liistoric and poetic glow-worm is the wingless female of the Euro- 

 pean Lampyris nocfiluca, Linn. But in most of our species both sexes 

 are furnished with wings. 



The Lampyrides are nocturnal insects, being sluggish by day, and 

 found sometimes on the ground, and sometimes resting upon the foliage 

 of trees, or upon the palings of fences. But at night they launch out 

 upon the wing, sometimes in immense numbers, especially in low mea- 

 dows, which they illuminate with their multitudinous flashes of plios- 

 phoreseuce. 



The following are the principal genera : 



A. Elytra complete, except in some wingless females ; head wholly or x^artially covered by the 

 thorax. 



B. One or more ventral segments, pale yellow, and luminous in the living insect. 



C. Antenna} dilated and compressed ; the abdominal segments of the males lobed at the sides ; the 



last segment only luminous LuciuOTA, 3 sp. 



C C. Antennje slender ; the abdominal segments simple ; one to three last segments luminous : 



Photinus, 26. 



A A. Elytra much abbreviated and attenuated ; head exposed ; antenna} branched ; phosphoresence 



uncertain .' Phengodks, 2. 



The Lucidota atra, Fab., supposed to be the same as the laticornis 

 of the same author, is a common insect. It varies from three to four- 

 tenths of an inch in length, and is of a deep black color, ^itli the mar- 

 gin of the thorax pale yellow. The genus Photinus, Laporte, contains 

 most of our lightning beetles. The P. jn/mlis, Linn., (Fig. 48,) is half 

 an inch or a little more in length, blackish, thorax with yellow margin 

 and red disk, with a blackish spot in the center ; tlie elytra have a nar- 



* We should perhaps also except the Ftdgora lanternaria of S. America, and the F. candelaHa, and 

 the Btiprestis ocellata of China, and a few other insects which have been reported to possess luminous 

 properties. But the testimony with regard to all of them is very couHicting, even with respect to the 

 liist mentioned, the lumiuousuess of which has been generally beUeved. 



