•^2 ARTHROPODS 



Sphegidae. Mud wasps. 



Bodies rather long and slender; prothorax prolonged into a neck 

 in front; abdomen petiolated; legs long, spiny; mandibles long, 

 curved, sharp; antennae long and filiform. 



Pompilidae. 



Bodies rather long and slender; prothorax prolonged backward 

 to base of wings; wings large and broad; legs long and spiny, 

 slender ; antennae long and filiform, not elbowed, usually coiled ; 

 colors chiefly velvety black or indigo blue, often with red spots; 

 wings opaque, black, blue or yellow. 



Mutillidae. Stinging ants, cow killers. 



Males winged, females apterous; bodies hairy, black, red or yel- 

 low, spotted or banded ; ocelli generally absent ; females found run- 

 ning along hot roads or paths; males found about sunflowers, etc. 



Formicidae. Ants. 



Males and females winged at maturity; neuters wingless; bodies 

 rather smooth, slender ; colors usually red, yellow or brownish 

 black, rather shiniijg. Living in colonies in all situations ; females 

 largest, males and neuters smaller. 



Section 2. Piercers. Provided with an unmodified ovi- 

 positor, or at least without poison glands. 



Chrysididae. Cuckoo flies (parasitic). 



Ocelli present; antennae thirteen-jointed, elbowed; maxillary 

 palpi five-jointed, labial, three-jointed; ovipositor stinglike, long- 

 jointed, but no poison gland ; abdomen ventrally somewhat hollowed 

 out ; body firm, coarsely punctured ; colors usually shining green 

 or black. 



Ichneiimonidae. Ichneumon parasites. 



Bodies long, slender ; ovipositor long, usually exserted ; antennae 

 long, slender, filiform, many jointed, not elbowed; internal para- 

 sites on other insects, very beneficial. 



Proctotrypidae. Egg parasites. 

 Bodies very small, slender; antennae usually long and slender; 



