NOOTUAS. 



339 



546. The Broad- Bordered Yellow Underwing 



(Tryphcena fimbria) . 



546. THE BROAD - BORDERED YELLOW 

 UNDERWING. The antennae are white at the 

 base : the colour of the fore wings is pale wain- 

 scot-brown, or rich mahogany-brown, or rich 

 olive-green; the specimens of the mahogany- 

 brown colour are comparatively rare, those with 

 the wainscot-brown and olive-green colour are 

 equally common ; the two discoidal spots are 

 very clo.*e together, and sometimes, although 

 rarely, united ; they are clearly marked by a 

 pale and very fine outline", but the enclosed 

 area differs little from the general ground- 

 colour ; there is a pale transverse bent line 

 beyond the discoidal spots, and another pale 

 line nearly straight, parallel with the hind 

 margin : the area enclosed between these two 

 lines is paler than the rest of the wing, and 

 has a darker blotch on the costal margin ; the 

 hind wings are dark orange at the base and 

 on the hind margin, between which parts 

 intervenes a broad band of the most intense 



black : the head and thorax are of the same 

 colour as the fore wings; the body is dark 

 orange. 



The CATERPILLAR rolls in a ring when 

 touched, feigning death and falling off its food- 

 plant : it is smooth, cylindrical, gradually 

 diminishing in size from the twelfth segment 

 towards the head, which is remarkably small 

 for the size of the caterpillar : the colour of 

 the head is shining clay-brown, mottled and 

 reticulated with darker brown; the body is 

 clay-brown, mottled, and velvety ; the second 

 segment has three narrow longitudinal pale 

 lines ; on each side of each segment there is 

 an indistinct oblique pale stripe; along the 

 back is a median series of obscure darker 

 marks, seated in the interstices of the seg- 

 ments ; the spiracles are pale and each seated 

 in a dark brown mark ; on the twelfth segment 

 is a pale and a dark transverse mark; the 

 belly, legs, and claspers. are paler than the 

 back. The egg of this beautiful moth is 

 laid on birch (Betula alba), sallow (Salix 

 caprea), and several other trees early in the 

 autumn, and the young caterpillar remains on 

 the tree until the approach of winter, when it 

 descends to the ground and hybernates : in 

 the spring it ascends the trunk every night as 

 soon as it is dark, and devours the newly-ex- 

 panded leaves, then very small, again retiring 

 to the ground before the approach of daylight. 

 It is generally full-fed before the middle of 

 May, when it finally changes to a CHRYSALIS 

 on the surface of the ground. When full-fed 

 it is very conspicuous on the almost naked 

 twigs of the birch, and is readily procured by 

 collectors who seek it by lamp-light. 



The MOTH appears on the wing from June 

 to September, and occurs not unfrequently 

 in most of our English, Scotch, and Irish 

 counties. (The scientific name is Tryplitena 

 Jimbria.) 



Obs. Like the last, this species is remark- 

 ably rich in colour and attractive in appear- 

 ance, but differs from that in being subject to 

 three very marked varieties of colour : those 

 of the mahogany- brown tint are very un- 

 common. 



