CLASSIFICATION AND ORIGIN OF INSECTS 1415 



others, having a long, soft body without wings, but 

 with an immense head, and very large, strong jaws. 

 These individuals act as soldiers, doing apparently 

 no work, but keeping watch over the nest and at- 

 tacking intruders with great boldness. (4) Apterous 

 eyeless individuals, somewhat resembling the winged 

 ones, but with a larger and more rounded head; 

 these constitute the greater part of the community, 

 and, like the workers of ants and bees, perform all the 

 labor, building the nest and collecting food. (5) 

 Latreille mentions another kind of individual which 

 he regards as the pupa, and which resembles the 

 workers, but has four white tubercles on the back, 

 where the wings afterward make their appearance. 

 There is still, however, much difference of opinion 

 among entomologists with reference to the true na- 

 ture of these different classes of individuals. M. 

 Lespes, who has studied the same species, describes 

 a second kind of male and a second kind of female, 

 and the subject, indeed, is one which offers a most 

 promising field for future study. 



Another interesting family of Neuroptera is that 

 of the Ephemerae, or Mayflies, so well known to fish- 

 ermen. The larvae are semi-transparent, active, six- 

 legged little creatures, which live in water; having 

 at first no gills, they respire through the general sur- 

 face of the body. They grow rapidly and change 

 their skin every few days. After one or two moults 

 they acquire seven pairs of branchiae, or gills, which 

 are generally in the form of leaves, one pair to the 

 segment. When the larvae are about half grown, the 

 posterior angles of the two posterior thoracic seg- 



