the Life History of Trichoptilus pallidum. 149 



hairs. Anal plate carries six hairs on either side, the spiracles are 

 black but not very large or prominent. 



Third Instar. — 3"5 mm. long before feeding much ; it lias now 

 quite the adult "plumage," though the secondary hairs are fewer 

 and much smaller than in last instar. Tlie tubercles are on or rather 

 form almost raised humps. The secondary haii's are four on I and IT, 

 two or three of them very small and inconspicuous, one on III, none 

 on IV and V or on VI. These secondary liairs are white and 

 clubbed. The primaries arise from black points, are ochrcous, with 

 white clubbed tips. The skin points, wanting in 1st instar, trans- 

 parent and sparse in 2nd, are now abundant. The tubercular areas 

 are free from them ; these areas, which probably correspond to the 

 earlier tinted scutes which are not present now. Lave a little 

 differentiation of colour and texture to mark them off from the 

 surrounding skin. The larva is still very transparent and flimsy 

 looking. The white under the tubercles seems subcutaneous, as does 

 also the red-brown of the dorsal stripe and of a great part of the rest 

 of the larva. The red is however in marks or marblings, but not in 

 continuous streaks. Two hairs on head and on meso-thorax are long 

 but only little longer than the longer ones on the abdomen. The 

 longer hairs are from 0"35 to 0-4 mm. long, not, some three times as 

 long as others, as in previous instar. The prolegs are long props, 

 slightly bulbed at end and with seven dark crotchets round the inner 

 margin. The six eyespots are very prominent, more than hemi- 

 spheres. The head is translucent with ochreous marblings. A large 

 black mark under eyespots, but three of them escape it, or seem to 

 do at certain angles and look quite white. 



There is a short hair ventrally close to middle line in abdominal 

 segment without prolegs, probably present in other instais though 

 not noted. The last joint of the true legs is markedly long and 

 slender. 



These detailed notes on the progress of individual larva 

 were much broken up and rendered of little use by the 

 way in which the larva succeeded in hiding themselves, 

 as well as cases of wandering away to another plant, really 

 getting lost, etc. This occurred with larvse each on a 

 separate plant. In several cases, I gave up the larva for 

 lost, but it duly reappeared again. These facts apply 

 most to the youngest larvae, and are the ground for my 

 suspicion that in the autumnal larvae I may have been 

 wrong in thinking they all fed only in the centre of the 

 plant, though the extrusion of frass there, in one instance 

 observed, could only be compatible with the larva being 



