34 



MISC. PUBLICATION 318, U. S. DEPT. OF AGRICULTURE 



Figure 85. — Bald-faced hornet. 



reddish yellow with golden hair, and has four wings. This insect has 

 complete life changes. The mouth parts are fitted for chewing and 

 lapping. This wasp, Ammobim ichneumonea, in the adult form feeds 

 on flowers, and the larva feeds on paralyzed grasshoppers. It hiber- 

 nates in a cell in the ground, probably as a full-grown larva or pupa. 

 Because it destroys grasshoppers it can be considered beneficial. 



Bald-faced hornet. — Another of the wasps, and one having a short, 

 thick body, is the bald-faced hornet. The queen of this species is 

 about seven-eighths of an inch long ; the workers are somewhat smaller. 



This wasp is black with creamy- 

 white markings and has four wings 

 which enable it to fly rapidly. The 

 mouth parts are fitted for chewing 

 and lapping. The bald-faced hor- 

 net also is able to inflict a painful 

 sting. The adult feeds on flowers, 

 fruit juices, and honeydew; the 

 larva feeds on softened insects. This 

 insect has complete life changes ; the 

 adult queens hibernate in sheltered 

 places such as under bark or in 

 crevices. When the days begin to 

 warm in the spring, the queen starts the construction of her paper- 

 like nest, and as soon as sufficient comb is built, begins to rear her 

 brood. As the season advances and the first workers emerge, the 

 nest is increased in size by tearing out the inner lining, widening the 

 layers of comb, and adding more layers of comb below. Additional 

 layers of the paperlike covering of the nest are then built on the out- 

 side. This material consists of wood fibers mixed with a salivary secre- 

 tion, is waterproof and very tough, and affords protection for the nest. 

 The nest sometimes attains the size of a foot or more in diameter. 

 The economic importance of this insect is questionable, although it 

 does kill some destructive insects. The bald-faced hornet shown here 

 is Vespula maculata, and belongs to the order Hymenoptera. 



Parasitic wasps. — No doubt many persons have encountered wasp- 

 like insects with long appendages like the one shown here, but have- 

 not realized that these 



threadlike structures are 1 



for &gg laying. The j 



insect illustrated here, \ 



Megarhyssa lunator, is * jfc. 



an inch or more long. 



The egg-laying structure, 



or ovipositor, may be 3 



inches long. The body 



is very slender, light 



brown, with lighter chev- FlGURE 86.— Parasitic wasp. 



rons along the sides of the abdomen. Although the adult has chew- 

 ing mouth parts, it is doubtful if it does very much feeding, but the 

 larva feeds by sucking the blood from the larva of the pigeon horn- 

 tail. The long egg-laying appendages permit this wasp to drill 



