150 ALLANTUS ARGUAT[JS. 



are sometimes spotted with black; the edges of tlie 

 abdominal segments have generally greenish-yellow 

 lines, but not rarely they are entirely black. 



The greenish-yellow marks on the pleurae readily 

 separate this insect from the other British species, 

 except from flavipes, which differs from it markedly in 

 coloration. 



B/udow (1. c.) is of opinion that arcuatus, dispar 

 (flavipes) and Schaefferi are varieties of the same 

 species, which he would name marginellus, Pz. He 

 says that the larvse* of the three species just mentioned 

 are coloured alike, being of a green colour, which 

 varies to a clearer or deeper hue. Before pupating 

 they are brownish, many times bearing brown spots. 

 He found them on Alnus, Umlelliferce, and Achillea, 

 but always immediately before they were preparing to 

 spin up, so that he was in ignorance of their precise 

 habits, and he seems to be even in doubt as to the 

 particular food plants. 



With this opinion of Eudow's regarding the specific 

 identity of the three species we cannot agree, and it 

 is evident that flavipes has a very different larval 

 history from arcuatus. 



Arcuatus is one of our commonest saw-flies. It is 

 found everywhere in June and July, the imago fre- 

 quenting the flowers of Ranunculaceat, Umbelliferce, 

 and Composite. It is very carnivorous, and will often 

 attack insects as big if not bigger than itself. The 

 species is equally common everywhere on the Con- 

 tinent. 



* "Larva opaca, yiridis, pruinosa, segmentum marginibus flavo- 

 viridis, oculis magnis brunneis ; capite viridi, crasso. In alni," 1. c., 

 p. 137. Andre refers this description of larva to Scliae/eri. 



