362 



NATURAL HISTORY OF ARTHROPODS. 



develop under favorable circumstances in a year, but many of them require sever;;! 

 years to attain full growth. 



The Elateridae not only show their relationship to the Lampyridae by anatomical 

 characters, but also by the possession of luminous organs in a few species, these lumi- 

 nous organs being found in the larvae of a number of species, and being long since 

 observed on the images of Pyrophorus. 



FIG. 413. Stages of an Elaterid (Alans). 



The true Elaterida? have the posterior coxa? laminate, and the labrum visible and 

 free. Jfelanactes piceus is a very shining, black species, about one inch long, found 

 upon the Atlantic coast of North America as far north as Massachusetts. M. morio, 

 a somewhat smaller species with striate elytra, is found in the same regions. Larvae, 

 supposed to belong to Melanactes, are quite brilliantly luminous. 



It is, however, to the genus Pyrophorvs, which contains about a hundred species of 

 Elaterida?, all from tropical America, that we must turn for the most brilliant forms 

 of luminous insects. Pyrophorus noctiluc'KS, common in the West Indies and Brazil, 

 and in common with a few allied species called the cuciu/o by the West Indians, is 

 from 1.50 to 1.75 inches long. Its color is a rusty brown, approaching black. Upon 

 each side of the prothorax, near its basal angles, is a convex, oval lantern, which, 



