of which two are orbicular, and placed on each 

 side, and one is central, fusiform, sometimes 

 rounded; scutel black; elytra sanguineous, with 

 punctured striae, interstitial lines flat, with dilat- 

 ed punctures ; four black spots on each elytrum, 

 placed 1, 2, 1, the latter largest. 



Length seven-twentieths of an inch, exclusive 

 of the rostrum. 



OBSERVATIONS. 



We introduce this familiar insect, and a va- 

 riety of it, chiefly for the sake of comparison 

 with another species, which has many characters 

 in common with it. A slight inspection of the 

 plate will, however, at once disclose the differ- 

 ences by which we will always be enabled to 

 distinguish them from each other. 



The tredecim-punctata, which does not appear 

 to be injurious to any useful plant, may be found 

 in considerable numbers on the milk-weed, or 

 wild cotton (Asclepias syriaca), which is very 

 common in the neighbourhood of Philadelphia, 

 growing on the banks of streams of water. The 

 insect seems to be a pretty general inhabitant of 

 the United States ; I have found it in Missouri, 

 Arkansa, and the North West Territory, as well 

 as in Pennsylvania. 



PLATE IX. 



