FHYTOPHAGA. 389 



is, therefore, most important that all rubbish should be removed and 

 destroyed ; the quicker the bines grow, the less the injury that will be 

 caused (as is the case with turnip crops when attacked by the turnip- 

 fly), and therefore the addition of a little rich manure to the ground is 

 very beneficial, as suggested by Miss Ormerod (Manual of Injurious 

 Insects, p. 105); P . attvnuata is, apparently, almost confined to the hop, 

 and is therefore a very local species ; but the very abundant and more 

 or less omnivorous species, Plectroscelis concinna, also in some seasons 

 does great damage to the hop crop as before noticed. 



The British species may be divided as follows: 



I. Posterior tibiae longer and more slender, almost straight 

 on their under-side; posterior femora moderately 



broad. 



i. Forehead with two distinct and deep furrows be- 

 tween eyes, which cro-^s one another and form an X. P. ATTBNUATA, Koch. 



ii. Forehead with the furrows between the eyes absent 

 or more or less obsolete. 



1. Under-side black or mostly black. 



A. Sculpture of elytra stronger. 



a. Length 3^-4 mm. 



a*. Antenuee longer and thinner ; colour vari- 

 able, but upper surface usually bronze or 

 bluish-green, except front of head which is 

 reddish P. CHRYSOCEPHALA, L. 



b*. Antennae shorter and stouter ; head and 



thorax always reddish-yellow, elytra blue . P. CYANOPTBBA, 111. 



b. Length 2-2} mm. ; head black, thorax and 



elytra, except suture, testaceous P. AFFISIS, Payk. 



B. Sculpture of elytra finer. 



a. Head and thorax brassy-green, elytra reddish- 

 brown ; size larger P. LUBIDIPBNNI8, Kutt. 



b. Upper surface entirely bronze or blackish- 



bronze, 

 a*. Punctuation of thorax distinct and rather 



deep P. CCPRZA, Koch. 



(cupronitens, Fdrat.) 

 b*. Punctuation of thorax very fine. . . . P. INSTABILIS, Foudr. 



c. Upper surface blue or greenish-blue ... P. NAPI, Koch. 



2. Upper and under surface testaceous P. MAKCIDA, III. 



II. Posterior tibiae short, considerably arched on their 



under-side ; posterior femora very broad. 



i. Legs pitchy-black, posterior femora dark blue or violet P. DCLCAMAH.*., Kuch. 

 ii. Legs in part reddish or testaceous. 



1. Punctuation of thorax double, consisting of larger 



and smaller punctures ; size larger. 



A. Upper surface blue ; rows of punctures on 



elytra finer P. ciULCOXEKi, III. 



B. Upper surface bronze ; rows of punctures on 



elytra deeper P. HYOSCYAMI, L. 



2. Punctuation of thorax simple ; size smaller. 



A. Upper surface entirely reddish-testaceous . . P. LCTBOLA, Hull. 



B. Upper surface dark bronze P. PICINA, Marth. 



P. attenuata, Kuch. Elongate ovate, moderately convex, aeneous 



