no. i. BOMBYCINE MOTHS OF NORTH AMERICA— PACKARD. 217 



7. The larva is most gaudily colored and conspicuous in the last two stages; while in P. cynthia there are not so marked 

 differences between the different stages, though the last la the most variegated owing to the beautiful turquoise- 

 blue trappings. 



[The following notes on S. cecropia were made by Mr. J. Bridgham in 18S9:] 



The eggs hatched out in about 14 days, a few coming out in 12, and some as late as 18 and 

 (it is believed) in 21. When first hatched the larvae are moist, with hairs flattened down and 

 tubercles like small buff-colored swelhngs. Within 20 minutes the tubercles have raised to 

 high warts of a bright lemon yellow color, the black spines on them being very fine. It takes 

 from 20 to 45 minutes from the moment the shell is first chipped for the larva to emerge. Very 

 few have any trouble in coming out. They make the hole by biting quickly for a moment and 

 then resting. They do this about four to six times before the hole is large enough for them to 

 get out. No trace of the shell which they had bitten could be found inside or out of the empty 

 egg. They eat it, but do not eat any more than enough to make the hole. When, in 10 or 15 

 minutes the tubercles become bright yellow, the larva has the appearance of being powdered 

 with yellow pollen. The four tubercles forming the two dorsal pairs on the second and third 

 segments and the one on the eleventh segment are the largest from the beginning. The tuber- 

 cles take these shapes in the first 10 minutes. [Rough sketches are given showing the develop- 

 ment of the tubercles when buff, bright buff, bright yellow, very bright yellow, and very bright 

 and brilliant yellow.] For half an hour the brilliant transparent yellow color continues. It 

 then fades very slowly to buff, muddy gray-yellow, very dull yellow, and finally darkens to a 

 hard, shiny, horny black. 



The cecropias were so numerous in the West that they were a pest this last season to the 

 men who owned tree claims. They attacked the willow, the box elder, the Cottonwood, and 

 the ash. The willow produced the largest cocoons, the box elder the darkest, and the cotton- 

 wood very light-colored ones. The box elder suffered the most. A number of these western 

 cocoons were sent to me, and they all produced large and very tawny or reddish insects. Most 

 of them produced females. [From another note it appears that these came from Duluth and 

 the injury to trees referred to occurred in Dakota.] The insects invariably came from the 

 cocoons in the morning before noon. It took from 6 to 8 hours for them to fully develop. They 

 show no signs of mating for 24 to 48 hours from time of hatching, although placed together at 

 once. In no case did they mate during the day, but always in the early evening, the connection 

 lasting fully 24 hours, the female clinging to some support and the male hanging free and 

 motionless. They are not easily disturbed. Several attempts were made to mate one male 

 with two females in succession. In two cases out of five it succeeded. All attempts, however, 

 to mate one female with two males were in vain. 



Most of the cecropias came out the first half of July. The number of eggs laid by a female 

 was 200 to 300, half being laid within an hour or two of separation. Several females opened 

 before impregnation showed from 250 to 350 eggs. The male cecropia flies in the evening. I 

 have not had it come to the house (after females) until 9 or 10 p. m.; never in the daytime. 



[A form of S. cecropia raised in a temperature experiment was named ab. macula Reiff, 

 Zeitz. f. Wiss. Insektenbiologie, 1911, p. 235. The fore wings have near the margin a complete 

 series or row of black spots, corresponding with those on the hind wings, while the row of black 

 spots on the hind wings is very strongly marked. Mr. Reiff informs me that this came from 

 pupae collected on Long Island.] 



Cocoons of S. cecropia were carried to Paris, June, 1900. Males appeared June 24-27, 

 females July 4-6; eggs were laid July 7-10. Compared with a male and female raised by 

 Fallou at Champrosay, fed on Acer platanoicles, mine which came out in Paris showed no differ- 

 ences greater than between the two Fallou specimens, except that they were darker and wings 

 more opaque. The lines and spots show no varietal differences, but the wings [in the Fallou 

 moths] are distinctly paler. M. P. Mabille has reared three generations, a generation a year, 

 and says there is absolutely no difference. The ? is paler than usual, as in those reared by 

 M. Fallou. 



