44 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 39 



adult and larva are shown in figs. 44 and 45. Well known to the 

 fisherman is the hellgrammite, the tough, ferocious, leathery- 

 larva found under rocks in streams and prized for bait. This 



Fig. 44. — Megaloptera. The adult 

 of Sialis mohri, an alderfly. Actual 

 length 0.5 inch. Other members of 

 this order reach a length of 1 or 2 

 inches. They are mostly black, black 

 and white, or mottled gray in color. 



Fig. 45. — Megaloptera. The larva 

 of a species of Sialis. This form is 

 aquatic. 



larva belongs to the order Megaloptera and matures into the 

 large dobsonfly, Corydalis cornuta (Linnaeus), which often 

 attains a wingspread of 4 inches. 



Mecoptera 



Scorpionflies 



Insects of this order have two similar pairs 

 of delicate wings, each with a medium net- 

 work of veins. In repose the wings are laid 

 almost flat over the back. The mouthparts are fitted for chewing 

 and usually are lengthened into a beaklike structure, as in Pa- 

 norpa chelata Carpenter, fig. 46. The larvae, seldom found, breed 

 in damp woods. The adults, usually 0.5 inch long, are active in 



