IS 02.] 289 



caudal horn, which has heretofore been straight, is now curveil, of a yel- 

 low-green color, granulated with brown anteriorly; anal jihite yellow bord- 

 ered ; thoracic horns yellowish tipped. 



Before the next molting, the larva has increased to 1.6 imli in length, 

 with veiy little variation in color from that above noted. At this stage, 

 when the head has been withdrawn from its case, its whitish lateral lines 

 can be plainly seen through the skin of the first segment which covers it. 



The fourth and last molting was on xVug. 3rd, and the six following 

 days. The meltings, with but few exceptions, take place at night; thus, 

 nn the morning of the 3rd, twenty-three larvae had undergone the change, 

 since they were last observed on the evening of the 1st; none molted dur- 

 ing the day of the 3rd, but the following morning thirteen were found in 

 their new dress. A large proportion of the sphinges which I have rear- 

 ed, have also undergone their imago transformation during the night — an 

 observation the more interesting from its not being in obedience to any 

 general law governing the entire order of Lepidoptera, — for while from 

 twenty pupae of Pi/gsera albifrons Sm.Abb., which I had at one time in 

 my possession, each one emerged during the night, — from fifty cocoons of 

 Saturnia lo Fab., obtained by me from the eggs of one female, every one 

 made its exit in the day time. 



The above molting was attended with the following marked change of 

 coloration : larva tan color, with serrations and granulations lighter or 

 ochreous; head umber color, with granulations almost black, the lateral 

 stripes light brown, and mandibles shining black ; first segment of the 

 body anteriorly and thoracic horns exteriorly with whitish granulations ; 

 stigmata black, bordered with white, and divided by a white line, appear- 

 ing blue by contrast; caudal horn reddish-brown, and quite rough with 

 lighter granulations, some of which are tipped with a short hair; anal 

 plate and shields dark brown, with black granulations; legs tan color. 



The mature larva measures from 2.75 to 3.25 inches. Its coloration 

 was as follows: body reddish-brown ; head brown with indistinct lateral 

 stripes of lighter; collar, anal plate and shields, and exterior of pcolegs 

 brown granulated with black; tips of the thoracic horns with oblong white 

 granulations; dorsal serrations tipped with whitish or pink. 



The larva, as above described, was very unlike all the individuals of the 

 species that I have captured, which have uniformly been of a whitish-green 

 assuming a rose or violet shade when ready to enter the ground;* of my 



•■■■ My observations do not. confirm the opinion of Dr. Clemens, that thin cliange 

 fif <'o]nr is a sexual charnctorisf ie. 



