Description of a New Mackerel. xxxi 



to obtain his opinion with regard to its identity with any known species ; and a por- 

 tion of his reply is as follows : — " On comparing the preserved skin of our fish with 

 your representation, I observe some points of distinction, which, though slight, may 

 increase the amount of differences. Your fish appears to be less deep in proportion 

 to its whole length than the old mackerel ; the measurement being 2f deep by 15f s , 

 or as 1 to 5£ ; the old one 3j by 15f, or not quite 1 in 5, — and this is remarkable, 

 as your example was a female, and the roe large, as the time (July 6) would of itself 

 indicate. The mouth in your fish appears to be smaller, the angle of the gape not 

 placed so far back, and the superior maxillary bone is shorter and broader. The pos- 

 terior edge of the preoperculum is more rounded, — in our mackerel the lower two- 

 thirds of this edge is almost a straight and perpendicular line ; the anterior portion 

 of the lateral line appears to be more strongly marked." To this may be added, that 

 the adult common mackerel is distinguished from its younger condition by a dusky 

 mottled line, which runs along the side and separates the lateral line from the belly. 

 Nothing of this sort was found in this fish, though of full growth and large with 

 spawn. In reply to my suggestion of a name, Mr. Yarrell says, " Scomber punctatus 

 would be an excellent name for it, as referring at once to its most obvious external 

 markings." 



Jonathan Couch. 

 Polperro, Cornwall, 

 March, 1849. 



Art. V. — Descriptions of New British Aphides. 

 By F. Walker, Esq., F.L.S., G.S., &c. 



Aphides on the Geranium (Pelargonium). 

 Aphis extranea. 



The wingless viviparous female. — The body is green and oval : the antennae are 

 very pale yellow and not half the length of the body ; their tips are brown : the ros- 

 trum and the tubes are pale yellow with brown tips, and the latter are less than one- 

 twelfth of the length of the body : the legs are pale yellow, rather short and very 

 slender : the tarsi and the tips of the tibia? are brown. 



Aphides on the Sea-rocket (Cakile maritima). 



Aphis contermina. 



The wingless viviparous female. — The body is small, oval, rather flat, pale brown, 

 velvet-like, covered (especially beneath) with a white bloom : there are dark bands on 

 the back, interrupted in the middle and ceasing towards the hind part of the body : 

 the antenna? are black, brown at the base, and about half the length of the body ; the 

 fourth joint is shorter than the third ; the fifth joint is much shorter than the fourth ; 

 the sixth joint is much shorter than the fifth ; the seventh joint is nearly as long as 

 the fourth : the rostrum is pale yellow ; its tip and the eyes are black : the tubes are 



