662 



THE STUD Y OF INSECTS. 



by a number of species. In California there is a single repre- 

 sentative of a third genus, Polybia (Po-lyb'i-a). This genus 

 differs from the other two genera, in having the first abdom- 

 inal segment long and slender, forming a peduncle. Our 

 species is Polybia flavitarsis (P. flav-i-tar'sis). 



Polistes. In this genus the abdomen is long and spindle- 

 shaped (Fig. 789). The species 

 are black, ringed with yellow, or 

 are brownish. Their nests con- 

 sist each of a single comb, sus- 

 pended by a peduncle, and are 

 not enclosed in an envelope (Fig. 

 790). In the fall these fellows 

 are quite as familiar as the mud- 

 FIG. 789. Polistes. daubers, which they resemble in 



color. However, they are easily distinguished from these, 

 as the abdomen is not on such an absurdly long peduncle, 



FIG. 790. Nest of Polistes. 



and their wings fold like fans. They come into our houses 

 searching for warm crevices in which to pass the winter. 



Vespa. To this genus belong the wasps commonly 

 known as yellow- jackets and as hornets. With these 

 insects the body is comparatively short and 

 rather stout (Fig. 791); the abdomen is at- 

 tached to the thorax by a very short peduncle ; 

 the color is black, spotted and banded with 

 yellow or yellowish white. The species of this 

 genus enclose the combs of their nest with a 

 spherical paper envelope (Fig. 79 2 )- Any person FIG. 79 i. 



