HOW TO KNOW THE INSECTS 



Fis. 51. Isoperla bilineata Say 



Yellowish, with greenish hyaline win^-s. Head 

 yellow with a brov/n spot over the ocellar tri- 

 angle. Perhaps our most conimon species. Length 

 to tip of wings 10-14 mm. 



Stone flies are important aquatic insects from 

 the standpoint of fish culture. The nymphs make 

 good bait. Both nymphs and adults have two 

 tail filaments. The nymphs leave the v:ater and 

 crawl out on the bank or on logs Lo change into 

 the adult stage. A female may lay several 

 thousand eggs. The order is not large. Some of 

 our larger Iowa species are considerably over an 

 inch in length. 



Figure 51, 



15b 



Not as in 15a 16 



16a No appendages at end of abdomen. Tarsi five jointed. (Ant- 

 lions, Lacewlngs, Dobson flies, etc.) Figs. 52 and 174 to 177. 



Order XIX, NEUROPTERA p. 87 



Figure 52. 



Fig. 52. Chrysopa oculata Say 



When living, rather pale green 

 throughout; eyes golden. When 

 pinned, pale green to pale yellow- 

 ish brown. Len'.:th to tip of wings 

 12-17 mm. 



The T-yeuroptera once Included many 

 insects no longer associated ^:.Qth 

 the order. It still includes in- 

 sects representing a wide variation 

 of sizes, colors, and habits. Some 

 are seldomi seen. The order is not 

 large . 



16b Wings equal in size and with indistinct veins. Thorax In 

 front of wings very short. (Termites or White-ants) Fig. 53. 



Order IX, I SOPTERA 



Fig. 53. A V/hlte Ant. (Queen) 

 Retlculitermes f lavipes Kollar 

 The Common Northern Termite. 



Males and queens at swarming time 

 winged and dark brown or black. Wings 

 are broken off when a "Royal pair" 

 establishes their colony. Workers, 

 soldiers, and nymphs wingless, white. 

 See Fig. 55. 



There are but two species of ter- 

 mites known to Iowa. They are 



Figure 



44 



