MISCELLA.NEOUS PAPERS. 195 



only within the broad limits of the cabba.'^e family, but in several other 

 and widely separated botanical orders. 



It is in this matter of food selection for their young- that mistakes 

 most frequently occur. One summer 1 repeatedly found the eggs and 

 young larva; of one of our common hntieTiiies ('Fyraniies hunteraj upon 

 the leaves of the Mugwort (Artunesia). Anxious to learn whether 

 these would develop upon a plant so different in its properties, although 

 also a composite, from the bland and mucilaginous Anteuneria^ upon 

 which they are accustomed to feed, I transferred a number of fliem to 

 the rearing cage. The others also were examined from day to day, but 

 they did not thrive, and the dry and bitter leaves seemed distasteful to 

 them. Very few passed even the second molt, and all perished, both 

 out of doors and in, except a few upon which I had pity and provided 

 with a supply of their usual food. 



Here was a case in which the parent butterflies had been deceived 

 merely by the similar whity-green color of the leaves, and showed a 

 very fallible instinct indeed. Similar examples are found in the case 

 of the flesh flies which oviposit freely upon StapeUa in green-houses, 

 as well as in its native Africa, misled by its dark red color and car- 

 rion-like odor. Parasite and predacious insects are much addicted to 

 a change of diet, which sometimes, as in the case of the web-worm 

 tiger f Plachionus timldusj, until recently considered rather a rare cara- 

 biel, leads to a change from subterranean to arboreal habits, and from 

 a species of interest to the collector only to one of great value to the 

 horticulturist. Two years ago this insect was discovered in consider- 

 able numbers in the nests of the web-worm {Hyphantria cunea), in 

 which it was making itself a terror to the rightful occupants, greatly 

 reducing their numbers, and whose gregarious habit it may eventually 

 largely modify, causing their depression at a far earlier age than for- 

 merly. 



Variation of habit for protection under unusual circumstances is 

 often noticed. Thus the seventeen-year Cicada pupa, when emerging 

 from the earth after its long subterranean adolescence, on finding the 

 surface too wet for its convenience, extends its tunnel in tbe shape of 

 a compact clay tube several inches upward, and, leaving an opening 

 below, rests securely in the top of its little tower until ready for the 

 second transformation. As might be expected, no insects have shown 

 greater powers of adaptation, whether under unusual conditions of 

 nature, or of those imposed by man, than the bees and wasps and other 

 social species. From the time of Huber, whose sightless eyes pene- 

 trated so deeply into the mysteries of nature, it has been known that 

 the honey-bee could be made to build its combs perpendicularly upward 



