118 INSECTS INJURIOUS TO VEGETATION. 



these are short, and very thick, the back arching upwards very 

 much in the middle. I believe that they go into the ground 

 to tm-n to pupte. Should they become so numerous as seri- 

 ously to injure the lime and elm trees, it may be found useful 

 to throw decoctions of tobacco or of walnut leaves on the 

 trees by means of a garden or fire engine, a method which 

 has been employed with good effect for the destruction of the 

 larvae of Galeruca Calmariensis. 



The most common leaf-beetle of the family under consid- 

 eration is the blue-winged Chrysomela, or Chryso7nela ccerulei- 

 pennis of Say, an insect hardly distinct from the European 

 Chrysomela Polyg-oni, and like the latter it lives in great num- 

 bers on the common knot-grass [Polygonum aviculare), which 

 it completely strips of its leaves two or three times in the 

 course of the summer. This little beetle is about three twen- 

 tieths of an inch long. Its head, wing-covers, and body 

 beneath are dark blue ; its thorax and legs are dull orange-red ; 

 the upper side of its abdomen is also orange-colored ; and the 

 antennae and feet are blackish. The females have a very odd 

 appearance before they have laid their eggs, their abdomen 

 being enormously swelled out like a large orange-colored ball, 

 which makes it very difficult for them to move about. I have 

 found these insects on the knot-grass in every month from 

 April to September inclusive. The larvae eat the leaves of 

 the same plant. 



Having described the largest, the most elegant, and the most 

 common of our Chrysomelians, I must omit all the rest, except 

 the most splendid, which was called Eumolpus auratus by Fa- 

 bricius, that is, the gilded Eumolpus. It is of a brilliant golden 

 green color above, and of a deep purplish green below; the 

 legs are also purple-green ; but the feet and the antennae are 

 blackish. The thorax is narrower behind than the wing- 

 covers, and the rest of the body is more oblong oval than in 

 the foregoing Chrysomelians. It is about three eighths of an 

 inch long. This splendid beetle may be found in considerable 

 numbers on the leaves of the dog's-bane {Apocynum AndroscB' 

 mifolium)^ which it devours, during the months of July and 

 August. The larvae are unknown to me. 



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