88 Studies on Life-history of Bombycine Moths. 



2. Great increase, in stage II, of hairs, the unipiliferous warts 

 transformed to verticillate polypiliferous warts. At end of stage 

 II the infra-spiracular white line appears. 



3. Assumption in stage III of Glaucopidian characters. Appear- 

 ance of the subdorsal white stripe, becoming yellow at the end of 

 the stage. The yellow dorsal and subdorsal hairs appear. Appear- 

 ance in stage III of the dorsal black tufts on abdominal segments 1 

 and 8. 



4. Appearance in stage IV of black tufts on abdominal segments 

 •2 to 7. 



5. The head previously black, becomes red in the penultimate, 

 or 5th, stage. 



G. A decided change in coloration from the penultimate to the 

 final stage, the hairs of the latter stage being all yellow, with no 

 black dorsal tufts. 



It will be seen that in stages I and II the larva resembles that 

 of the Arctians; it is minute, not easily detected by birds, and 

 feeds on the leaves of plants enjoying on account of its small size 

 and neutral tints a comparative immunity from the attacks of birds 

 and the visits of insects. When the spiny hairs become dense and 

 gaily colored, and the larva a very conspicuous object, feeding as it 

 does on the spears of grass, it is protected from birds and insects 

 by its dense stiff spiny hairs, and like some, if not most, Arctian 

 larvae it is comparatively free from the attacks of ichneumons and 

 Tachinaj ; in fact I have not seen any Ctenucha larvae which have 

 been parasitized. 



Whether the moths, which fly not very rapidly in the bright sun 

 and are much exposed to the attacks of birds, are distasteful or not 

 to birds remains to be proved by experiments, which I have been 

 unable to make. They do not give out the strong odor of Leu- 

 carctia and other Arctian females. 



Hibernation of the lai-va in the two la^t stages. — Like some 

 Arctians, as Pyrrharctia isabella ; Ctenucha virginica and the 

 llocky Mountain species (probably Ct. cressonana), kindly sent 

 me by Mr. Cockerell, wintered over in the larva state, but while 

 F. isabella hibernates in the final stage, that of Ctenucha, whether 

 near the coast of New England or in the higher elevations of the 

 Kocky Mountains, does not attain the final stage before the winter, 

 as the eggs are not laid before midsummer (those of Arctians are 

 laid early in June), so that the larva does not have time to com- 



