Nerve-winged Insects; Scorpion-flies; Caddis-flies 231 



verge of a deep pit (Fig. 320). The loose sand of the pit's edge slips in and 

 down, and the frantic struggles of the unlucky forager only accelerate the 

 tiny avalanche of loose soil and sand that carries it down the treacherous 

 slope. Projecting from the very bottom of the pit is a pair of long, sickle- 

 like, sharp-pointed jaws, adapted most effectively for the swift and sure 

 grasping and piercing and blood-letting of the trapped victims. The body 

 of the ant-lion (Fig. 319) is almost wholly concealed underneath the sand; 

 only the vicious head and jaws protrude above the surface in the pit's depths. 

 Comstock has seen the ant-lion throw sand up from the bottom, using its 

 flat head like a shovel in such a way that the flung sand in falling would 

 strike an ant slipping on the slope and tend to knock it down the side. Ant- 

 lion pits are to be found all over the country, in warm, dry, sandy places. 

 The ant-lions can be brought home alive, and kept in a dish of sand, where 

 their habits may be observed. 



The adult ant-lion (Fig. 321) is a rather large, slender-bodied insect 

 with four long oar-shaped gauzy wings, thickly cross-veined and usually 

 more or less spotted with brownish or black. The eggs are laid in the sand 



FIG. 321. Adult ant-lion, Myrmeleon. (Natural size.) 



and the freshly-hatched larvae or ant-lions immediately dig little pits. When 

 the larvae are full-grown and just how long this takes is not accurately 

 known each forms a curious protecting hollow ball of sand held together 

 by silken threads, lines it inside smoothly with silk, and pupates in this cozy 

 and safe nest (Fig. 320). The larva is said to lie for some time, even through 

 a whole winter, in this cocoon before pupating. The life-history of no ant- 

 lion species is yet thoroughly known. 



The family Myrmeleonidae includes eight genera, which are usually 

 grouped into two subfamilies as follows: 



Antennae nearly as long as wings ASCALAPHIN^E. 



Antennae not one-third as long as wings MYRMELEONIN^:. 



The subfamily Myrmeleoninae includes the true ant-lions with habits 

 in general as already described. The five genera in it may be distinguished 

 by the following key: 



