1913] Rau — Notes on Duration of Pupal Stage in Certain Lepidoptera 161 



posterior margin on each side of segments two and three, situated a short distance 

 in from the lateral bands and extending far beyond the end of the body; others 

 very small, occupying similar positions on segments four and five; these appear to 

 be the only dorsal hairs. Genitalia with long, slender external appendages, not 

 heavily chitinized. 



Measurements: 

 cf , length 1.000 mm. Width 



Head .246 .344 



Prothroax .100 .278 



Metathroax .196 .360 



Abdomen .623 .754 



NOTES ON THE DURATION OF THE PUPAL STAGE 

 IN CERTAIN LEPIDOPTERA. 



By Phil Rau. 

 St. Louis, Mo. 

 1. Grapta interrogationes Fab. 

 The larva? of this insect were observed upon their food-plant, 

 the hop vine, from the time of pupation to the time of emergence 

 as adults, covering the period from August 28 to September 21, 

 1910. The duration of the pupal period was as follows: 

 Days. No. of insects. 



9 1 



10 6 



11 2 



12 



13 2 



We see that in these eleven individuals this period varied from 9 

 to 13 days, in most of them 10 days. Mr. W. H. Edwards 1 

 finds that the duration of the pupal stage at Coalburgh, West 

 Va., is from 7 to 11 days, a little shorter than at St. Louis. 



2. Samia cecropia Linn. 



The notes on three insects of this species are as follows : 



~ Date of Date of ^ 



Sex, , . „ Duration, 



pupating. Emerging. 



c? 7/20/'10 6/3/'ll 318 Days. 



9 7 27 '10 6/5/'ll 313 '" 



9 7/15/'ll (I 4 '12 324 



i Can. Ent. Vol. XV. p. 201. 



