LETTUCE BLIGHT. 285 



wings, but were similar to the larvae in all other 

 respects, except in being larger ; they were exactly a 

 line in length. On placing some of the lettuces 

 under a bell glass, several of the perfect insects ap- 

 peared on the 3rd of September; others following in 

 succession for some time afterwards. These were of 

 two colours, perhaps characteristic of the two sexes. 

 Some had the head and thorax dusky brown; the 

 abdomen pale dusky, tinged with greenish-yellow ; 

 the legs dusky, with the joints rather darker : others 

 inclined generally to ochraceous-yellow, especially 

 the abdomen, and the collar between the head and 

 thorax.* 



Amongst the larvae at the roots of one lettuce I 

 observed a single specimen of the larva of some 

 other totally different insect, which appeared to be 

 feeding upon them. This latter was vermiform, and 

 much attenuated towards the anterior extremity, 

 which was very protractile ; it was of a pale green 



* If the above be an undescribed species of Eriosoma, which 

 is extremely probable, from the little attention which has been 

 paid to the insects of this family, it might be named E. lactucte, 

 and thus characterized : 



E. capite et thorace fuscis: abdomine oblongofuscescenti-ochraceo, 

 vel viridi-ochraceo ; pedibus fuscis, articulis saturatioribus. 



Long. 1. lin. JHa&.ad radices lactucse sativse. 



Possibly it may be the Aphis radicum, briefly alluded to by 

 Kirby and Spence, (vol. ii. p. 89,) as deriving its nutriment from 

 the roots of grass and other plants. There are, however, without 

 doubt, several species of these root Aphides. I have occasionally 

 observed another, besides the one described above, at the roots of 

 the Lysimachia nummularia, when growing in a pot in my garden, 

 and rendered unhealthy by being kept too dry. This was like- 



