HOW TO KNOW THE INSECS 



Fig. 234. Megarhyssa lunator Fat). 



Light chestnut brown. Abdomen with 

 row of V-shaped yellow marks on each 

 side, these bordered with black. 

 Darkened areas on wings brovm. A para- 

 site of the Pigeon-Tremex. Length of 

 body 22-40 mm. 



This large family includes some small 

 wasps, but most of its members are of 

 medium or large size. They are mostly 

 parasitic on caterpillars or other in- 

 Figure 234. soct larvao and thus do a valuable 



piece of work in keeping these pests 

 from becoming too numerous. 

 10b Cells M1 and 1st M2 fused into one cell. (The Braconid 

 Wasps.) Fig. 235. Family 12, BRACONIDAE 



Fig. 235. Chelonus texanus Cress. 



Head, thorax, abdomen and anten- 

 nae dull black; two sub-basal spots 

 on abdom.en, yellowish v/hite. Wings 

 whitish. Legs in part black, 

 marked irith yellowish red. Length 

 about 5 mm. (From U.S.D.A.) 



In habits and appearance the 

 Braconids are much like the Ichneu- 

 mon wasps. Some are of medium size 

 but most of them are small. Some 

 are so small that they undergo 

 their entire development within 

 the body of a plant louse. We have 

 counted over 500 Braconid larvae 

 within the body of what appeared to be a fairly healthy tomato 

 worm. The two families are distinguished by the wing characters 

 mentioned in the key. 



11a No closed cell in back wings 12 



lib Back wings with one or more closed cells 13 



12a Black, wasp-like insects with slim abdomen four or five 

 times as long as thorax. Antennae long and filiform. Fig. 236. 



Family 27, PELECINIDAE 



Fig. 236. Pelecinus polyturator 

 Drury 



It is the one Iowa species of 

 this family. Shiny black, length 

 about 75 miTi. The female here 

 shoi/m is fairly common. The male, 

 which has a much shorter abdomen, 

 is rare. It is parasitic on 

 white grubs. 



Fig\iT-e 235, 



Fiimre 256. 



110 



