Studies on Life-history of Bornhycive Moths. 71 



golden-yellow. The black pencils are now large and well developed, 

 and now the first six abdominal segments have well-developed dorsal 

 tufts. This is due to the increase in numl)er and size of the hairs 

 arising from the inner side of the median dorsal tubercles or warts. 

 In the fully fed larva they are still denser, and form the series of 

 median dorsal tufts, eight in all, one to each segment. Compared 

 with the final stage, the body is still visible through the hairs, and 

 the white infraspiracular band is still in part retained, while the 

 radiating hairs are paler, shorter and sparser, and less silky. 



Stage V and lasl.^ — Length 30 Him. (Maine, on willow, Septem- 

 ber 10th to 15th.) It is of the same size as H. maculata,"^ also on 

 the willow in Maine. The head is black, but with the anterior 

 division of the clypeus, together with the basal joint of the antennae, 

 labral lobes, labium and maxillge, white with a yellowish tint. The 

 body is black, but beneath pale livid yellowish along the middle. 

 Thoracic legs pale pitchy; abdominal legs pale flesh yellow. Spi- 

 racles whitish. The tubercles are black, but the hairs radiating from 

 them are dense, and all uniformly pale golden-yellow, those of the 

 dorsal median wedge-shaped tufts dusky at the end. The last of 

 these tufts is slightly longer than the others. There are two long- 

 black pencils arising from the 2d thoracic segment and projecting 

 nearly horizontally in front ; a second pair of similar black pencils 

 from the third thoracic segment, the latter giving rise to a pair of 

 lateral whitish pencils. A few long black hairs are mixed with the 

 long white hairs projecting from the prothoracic segment and reach- 

 ing over the head. Two irregular white pencils, but slightly dis- 

 tinguishable from the other white hairs, project out from behind at 

 the end of the body. 



On the thoracic segments between the 1st and 2d pairs of black 

 l»encils are, on the 2d and 8d thoracic segments, two pale yellowish- 

 ochre dorsal patches, which only become visible when it is creeping; 

 in fact these two segments are yellowish-ochre above, with blackish 

 patches. 



1 As those raised from the white ash were poorly and irregularly fed, they 

 were much less developed than those feeding wild on the willow, and which 

 reached maturity early in September. The ash caterpillars were only 25 mm. 

 in length, and the yellowish hairs even much paler than in normal larvae. 

 The median dorsal wedge-shaped tufts in all are dusky at the end, the inner 

 hairs of the tufts being blackish, either the whole hair or the ends only. 



2 In my report on Insects Injurious to Forest and Shade Trees, p. 353, this 

 caterpillar is wrongly referred to as probably H. maculata. 



