SOS FAMILY XL. LAirPYRTDii;. 



The fireflies are medium or small-sized, elongate or oblong, 

 beetles of soft stnieture, mostly plain l)laek or brownish in color 

 and often having' the thorax bordered with red or yellow and ex- 

 panding into a thin projecting margin which, in many species, 

 covers the head. They have the maxilhie exposed at the base and 

 bearing two ciliate lobes, the inner of vrhich is sometimes obsolete; 

 antennie serrate, usually ll-jointi-d and inserted on the front; elytra 

 thin, flexible, sometimes short and never strongly embracing the 

 sides of abdomen, the latter ^^'ith seven or eight free ventral seg- 

 ments; fi'ont coxal cavities laroe. transverse, the coxaj conical, with 

 large tmeliantins; middle coxip oblique, usually contiguous; hind 

 coxfB transverse and prominent; legs long, slender, often com- 

 pressed; tarsi 5-,jointed. not lobed beneath, the fourth joint more or 

 less bilobed. 



The name "Lampyrida?" is derived from a Greek word m.eaniiig 

 '"to shine." and refers to the property above mentioned which many 

 of the larger forms possess, viz., that of emitting a phosphorescent 

 or luminous glow. This light-giving apparatus is located on the 

 under side of one or more segments of the abdomen and is com- 

 posed of a specialized portion of fatty tissue, situated directly under 

 the soft chitinous cover and thickly supplied with nerves and fine 

 tracheal branches. ' ' The cells of this himinous organ secrete, under 

 the control of the nervous system, a substance which is burnt dur- 

 ing the appearance of the light; this combustion takes place by 

 means of the oxygen of the air conveyed to the cells of the luminous 

 body l)y the trachea;, which branch profusely in it and break up 

 into capillaries." The burning takes place without producing 

 sensible heat, is controlled by the will of the insect and is intermit- 

 tent, being exhibited by flashes. It is a vital phenomenon and 

 ceases after death, but the hnninous segments can be recognized in 

 dried specimens by their yellow hue. 



That the light-gJvi,]o- po^-er is of espiM'ial importance to the true 

 fireflies, which all belong to the subfamily Tampyrina?, is sho^ra by 

 the fact that they usually have the eyes largely developed, and that 

 they are nocturnal insects, being sluggish by day, when they rest 

 upon the ground, the trunks ,,f tree> or the foliage of herbs or 

 grasses. The property of emitting light is possessed both by the 

 perfect insect and the larva^ the latter, as well as the wingless 

 females of certain species, being known as "glow-worms." Those 

 belonging to the other subfamilies aiv diurnal in habit and are 

 usually foimd upon flowers nr runnin- actively about over leav,>s in 



