6 :\IEMU1KS OF THE NATIONAL ACADEMY OF SCIENCES. 



of iiboiit -to ., the dull jiray coloring of tiio wings with the lichen-green iind fiesh color giving 

 the whole such a perfect appearance to a piece of rough hark that the deception is perfect.'' 

 (Riley in Packard'.s Everest Insects, p. 209.) 



On the other hand the white ground color of the species of Cerura, with their black lines and 

 .spots, make them very conspicuous, and it remains to be seen whether these are not warning 

 colors and whether they may not secrete a malodorous or bad-tasting fluid to render them 

 distasteful to l)irds. However this may be, the seci'etion is not sufficiently pungent or enduring 

 to prevent these moths from being eaten by Anthrenus larva' and other museum pests. 



OX THE LARVAL COLORATION OF NOTODONTID.E, AND THE ORIGIN OF SPOTS FROM LINES OR 



STRIPES. 



The observations hitherto made on the coloration and markings of lepidopterous larvw. with 

 especial reference to their origin, have been those of ^\'eismann and of Poulton on sphingid 

 caterpillars, and of Poulton and of Schroeder on the markings of geometrid larviv. 



In preparing our monograph of the Notodontidse we reserved for a later occasion a discussion 

 of the origin of the stripes and spots, blotches, ".nd discolorations which serve to protect most of 

 the larvic of this group from observation. What we have to offer, however, are only some facts 

 and conclusions derived from an examination of some living larv» and of the colored sketches 

 illustrating our work. 



Perhaps the most striking examples of the effects of lights and shadows in altering the color of 

 the green pigment of certain parts of the body is seen in the markings of smooth-bodied larva? which 

 feed among pine needles. In the larv« of Nematus and Lophyrus, the green larvfe of geometrid 

 moths, also the larvte of certain Noctuida?, including the European Pano/i.s pmipei'dd., also the 

 species of the sphingid genus Lapara (EUema), which habitually feed on the leaves of coniferous 

 trees, the white and red longitudinal stripes have evidently been produced by reflections from 

 the light and shaded portions of the leaf, while the red stripes are reflected from the red sheaths 

 of the needles. 



Ilumptf an means of ohliteration or concealment. — Mr. Al)bott H. Thayer truly says: ''As 

 soon as patterns begin, obliteration of the wearer begins." Thus a geometrid larva holding 

 itself out stiff like one of the twigs of its food plant, becomes lost to view. Some larva;, be 

 .saj's, "appear to be extensions of leaves," and this is admirably illustrated by the remarkable 

 caterpillar of Nerlce hlclentaia (Monogr. Bombycine Moths, I, Pis. XJX and XXHI). The pale 

 green and white shades of the body, the alternating oblique bars and stripes, blend with those of 

 the elm leaf on which it rests or feeds. This singular larva differs fi-om all other known 

 notodontian caterpillars, and in fact from those of any other family, in each abdominal segment 

 from the first to the ninth, bearing a large fleshj- two-toothed hump, the three largest on 

 segments three to five. Thus, as we have stated, " the outline of the back is serrate, and 

 perhaps mimics the serrate edge of the leaf of the elm on which it feeds;" the .serrations or 

 humps are not only of the size and shape of those of the elm leaf, but the jagged outline of each 

 double hump strikingly resembles that of a serration of the leaf, which is two or three toothed. 

 Besides this, the tips of the teeth of the humps are reddish brown, like those of the tips of the 

 leaf serrations. Moreover, the oblique dark and light lines leading up to the humps, as shown in 

 Miss Soule's excellent drawing (PI. XIX, fig. 4), strikingly resemble the light lateral veins of 

 the leaf and the shadows they cast. 



With little or no doubt the tubercles and humps of the notodontians. <^f certain tree-iiiha1)iting 

 noctuid larvie, as well as many butterfly larvte, besides the geometers, are obliteration marks, 

 and have arisen in away difficult to explain, but evidentlj' through a merel}' mechanical process, 

 and have been the means of giving a hold on life that unarmed caterpillars do not possess. 



The humped caterpillars of the notodontian subfamily Heterocampini^, especially of the 

 genera Ilyparpax and Schizura, are armed with high, often nodding, tubercles on the first, fifth, 

 and eighth, or first and eighth, abdominal segments. 



While the nutant or movable tubercles evidently so function as to frighten away other 

 insects and thus ward oft' the attacks of tachina flies and ichneumons, these and the other humps 



