260 CATERPILLARS AND THEIR MOTHS 



The caterpillars are rather delicate as they grow 

 older, having some disease which causes black spots 

 near the tubercles, or some of them, and usually proves 

 fatal. A larva thus affected should be removed at 

 once, as one seems to infect the others. 



On the fifty-fifth day the caterpillars began spin- 

 ning, having first become orange-pink on the dorsum. 

 They were three inches long. As soon as a crawler 

 turned pink we put it by itself in a box with leaves 

 that the others might not disturb it. 



The cocoons were brown, ovoid, rather irregular, 

 very thin, and had no loose end, as have those of 

 cecropia and promethea, nor were they double, as those 

 are. Leaves were spun around each cocoon. Out of 

 doors the caterpillar crawls down the tree and away 

 from it, and spins its cocoon among leaves on the 

 ground. 



Luna caterpillars are not found on the walks and 

 roads as often as polypliemus, probably because nut- 

 trees are less often planted by the roadside than are 

 maples. We often find them on white birch and oak, 

 especially on young trees. 



The moths are common almost everywhere, though 

 there is a popular belief that they are rare. Probabl}'^ 

 this is due in part to their food-plants, being forest 

 trees, less often planted near houses, and to the late 

 hours of the flying moths. Our naturalist doctor tells 

 us of seeing them around lights in a piece of wooded 

 road he has had to pass over between two and three 

 o'clock in the morning. 



The moths are of an exquisite pale green color, the 

 costa of the fore wings being purplish, and the color 



