1890.] THE YOUNG NATURALIST. 



.80 



Larva. — This species, being entirely an internal feeder is appar- 

 ently less distinctly and intensely marked than the allied species. It 

 is of a pale, shiny green colour, with darker green dorsal and sub- 

 dorsal stripes, the spiracles being situated in a raised whitish stripe, 

 the skin smooth. The following description by the late Mr. William 

 Buckler is very complete. It was made from larvae obtained in 

 August, 1870, by Mr. C. G. Barrett. " The larva when full grown, 

 is about three-eighths of an inch in length, rather thick and plump, 

 tapering much just at each end, the head small, the legs short and 

 placed much under the body, the skin smooth, shining and pellucid, it 

 is of a watery, greenish tint, showing a dark greenish dorsal vessel, 

 the sub-dorsal stripe rs also darker green than the ground colour ; and 

 this is bordered by an opaque whitish stripe, which lies between the 

 skin, and shows partially through its glossy surface ; another such 

 faint stripe shows through along the side, and below that is another, 

 somewhat inflated, on which are the spiracles, the head is black, and 

 so also is another plate across the middle of the back of the second 

 segment, which is divided in the centre by a thin line of the ground 

 colour, the anterior legs are black ; the tubercular dots above are 

 small and black, those along the spiracular region are rather larger, 

 and those along the thirteenth segment are larger still ; a black plate 

 is on the anal flap : it is noteworthy that each tubercular dot in this 

 Pterophorus has but a single hair " ('Entomologist's Monthly Mag- 

 azine,' Vol. VIII.. p. 154). To this description Mr. C. G. Barrett, 

 describing the manner in which the larva feeds, adds : — " The larva 

 of the second brood, when young, mines one of the smaller shoots of 

 Senecio aquaticus near the buds, afterwards it crawls further down, en- 

 tering one of the larger branches at the axil of the leaf (frequently de- 

 vouring the tender side shoot), and bores down the interior, feeding on 

 the pith until nearly full grown, when it again deserts its burrow, and 

 proceeds to the thick main stem of the plant, which it enters and there 

 feeds up, hollowing out a space in which to assume the pupa state. 

 In every case a round hole is left for the extrusion of excrement, and, 

 in the final burrow, this is placed exactly at the head of the pupa, so 

 that there is no difficulty about the egress of the perfect insect 

 (" Entomologist's Monthly Magazine," Vol. VIII., p. 154). So far the 

 larva of the first brood, that is, of the early spring brood, has not 

 been found, but Mr. C. G. Barrett writes : — "The larva of the first 



