HOW TO KNOW THE INSECS 



Fig^jre 226. 



3b Ovipositor bare 

 f I ies.) Fig. 227. 



Fig. 226. Tremox columba L. The 

 Pigeon Horn-tall. 



Brownish yellow, marked with 

 dark brown. Wings brownish yel- 

 low with light brown veins. Fig- 

 ure Is of female. Male has abdo- 

 men wholly brov/n and lacks ovi- 

 positor. The eggs are lain In 

 the trunks of oak, apple, elm and 

 other trees where the larvae bore. 

 Length 20-45 mm. 



This family Is a small one. The 

 members are elongate v/lth subcyl- 

 indrlcal bodies. The females 

 bore holes In the trunks of trees 

 with the stiff ovipositor and lay 

 one egg In a place. The larvae 

 develope as wood borers. 

 evident; antennae clubbed. (The Stem-Saw- 



Fami ly 3, CEPHIDAE 



Figure 227. 



Fig. 227. Cephus clnctus Norton 

 The Western Wheat-stem Sav.^fly. 



Black, shining; abdomen promi- 

 nently marked with three yellow 

 crossbands; wings smoky; legs 

 yellow. A pest of wheat ?nd 

 other small grains. Length 

 6-8 mm. 



The members of this family bore 

 into the stems of grasses and 

 other herbaceous plants and into 

 the young shoots of trees and 

 shrubs. They are insects of 

 moderate size, rather slender and 

 elongate 



4a Antennae clubbed; large insects. Fig. 228. 



Fami ly 6, CRABRONIDAE 



Fig. 228. Cimbex americana (Leach) 

 The American yawfly. 



Head, thorax and base of abdomen 

 black except for a bright yellow spot. 

 Remainder of abdomen brownish red. 

 Antennae yellowish brown. V/ings 

 smoky. The larvae feed on the leaves 

 of willow and elm. Length 20-28 mm. 

 (From U.S.D.A.) 



There are probably few species of 

 this family to be found in Iowa. The 

 larvae are grub-like but bear eight 

 pairs of pro-legs v/hich distinguish 

 them from either the caterpillars or 



beetle larvae. 



Medium sized species. (The Typical 



Fami ly 9, TENTHREDINI DAE 



Figure 228. 



4b Antennae not clubbed. 

 Sawf I ies) Fig. 229. 



107 



