118 Bulletin 76 



no other food than the frothy glue that protected the eggs from which they 

 hatched." The same is true of the caterpillars of this species. 



As the little caterpillars wander about the twigs they spin delicate 

 threads of silk so that after a time the branches which they have most 

 largely occupied are covered with the whitish threads. If they are disturb- 

 ed by jarring the branches, the little worms let themselves to the ground 

 by a thread of the same silk. This habit of spinning continues until 

 maturity, though much less of it is done in the later stages than in the 

 earlier. 



The growth of all caterpillars is extremely rapid and this great increase 

 in si«e is too much for the elasticity of the skin ; accordingly from time to 

 time it bursts open and slips off, or is shed. In the forest caterpillar there 

 are usually four changes of skin, or molts, before it reaches maturity, and 

 after the cocoon is finished, a fifth and last molt occurs. 



As we have seen, the caterpillars just from the eggs are very dark, but 

 in a few days they grow lighter except at the ends, and there is a dark line 

 along each side. After feeding and growing for two or three weeks the 

 larvae lose their old skins and appear in new ones. The interval between 

 the hatching, and this first molt undoubtedly depends upon the weather 

 and the abundance or scarcity of food. At this time the worms are half 

 an inch long. The color has changed somewhat with the change of skin, 

 for now there are two light lines just above the dark lines mentioned above 

 and these light lines become more evident as the worm grows. In many 

 specimens, the line of light spots, so prominent a feature of the full grown 

 worm, is indistinctly seen. About a week after the first molt the second 

 occurs. The worms have now increased to three fourths of an inch in 

 length. The row of light spots along the back becomes very distinct. Along 

 each side there is the dark line which first appeared, then above this is a 

 white line, then a pretty blue line, or rather band, for it fills the space be- 

 tween the lower light line and that above 1I;, then near the back is a yellow 

 line, and, more conspicuous than all, is the row of 10 or 11 spots of the form 

 well shown in plate III. At the end of another week, the larvae are ready 

 for a third molt. This brings little change in appearance except in size, the 

 length now being an inch. The markings are also brighter after the third 

 change of skin. In about two weeks the fourth molt takes place and the 

 worm is fully grown. The color and markings have not changed essen- 

 tially since the previous molt, but the length has increased to nearly or 

 quite two inches, as shown in figures 2 and 5. 



In figure 5, «,, which gives a view of the upper side of one segment, 

 enlarged about twice, the conspicuous oval or diamond shaped spot is seen 

 and behind it a small spot of the same color, on a ground of black. On 

 either side is seen the yellow line and beyond this-^^as the figure gives it— 



