H. W. LEWIS. 171 



Table of Genera. 



1. Abdomen petiolate Poly bia. 



Abdomen not petiolate 2. 



2. Abdomen fusiform, pointed at the base Polisles. 



Abdomen conical, truncate at the base Vespa. 



General Characters of the Genus Vespa. 



The species of Vespa are quite variable in their markings, and 

 they are all more or less punctured and hairy. The metathorax is 

 very short and truncate and the abdomen is sessile, broad and trun- 

 cate at the base, tapering gradually toward the posterior end. The 

 basal nervure joins the subcostal some distance before the base of 

 the stigma. These wasps are commonly known as hornets, yellow 

 jackets or wasps. Some make their nests in the ground, while 

 others attach them to the branches of trees or shrubs, or even under 

 the eaves of buildings, and in other inore or less protected places. 

 The nests constructed above ground are more or less globular and 

 entirely surrounded by at least two sheets of their peculiarly manu- 

 factured paper. As the number of individuals in a nest increases 

 and they become crowded for room they tear away the inner layers 

 and add others to the outside. 



Table of Species. 



1. Eyes extending nearly or quite to the base of the mandibles 7. 



Eyes remote from the base of the mandibles 2. 



2. Species black and white 3. 



Species black and yellow 5. 



Species brown and yelk)W crabro. 



3. Flagellum ferruginous beneath macula I a. 



Flagellum all black 4. 



4. The broad white borders on the third, fourth and fifth abdominal segments 



deeply notched or divided borealis. 



All the segments of the abdomen narrowly bordered with yellowish wjiite. 



inarjgfinata. 



5. Metathorax bearing two yellow spots behind ff riial<li. 



Metathorax not bearing two yellow spots 6. 



6. With yellow triangular spot beneath the base of the fore wing-diabolica. 

 Without a yellow spot beneath the base of the fore wing media. 



7. Species black and white coiisobriiia. 



Species black and yellow 8. 



Species black, yellow and brown riifa. 



8. Mesothorax bearing two longitudinal yellow lines 13. 



Mesothorax not bearing two longitudinal yellow lines 9. 



9. Antennae of female and worker all black - 11. 



Male, female and worker with scape yellow in front 10. 



TRANS. AM. ENT. SOC. XXIV. JUNE, 1897. 



