BULLETIN 1016, U. S. DEPARTMENT OF AGRICULTURE. 



a total of 56, or about 9 per cent, were infertile. In both instances 

 males were with the females at all times. 



NUMBER AND LENGTH OF INSTARS AND TOTAL LENGTH OF THE IMMATURE 



PERIOD. 



According to experiments conducted at the laboratory at Columbia, 

 S. C, in 1919, and again in 1920, the nymphs of this species molt five 

 times during their development from egg to adult, the same number 

 of times as do the nymphs of the squash bug (Anasa tristis De G.) 

 and the harlequin cabbage bug {Murgantia histrionica Hahn) . These 

 species, although belonging to different families from the- chinch 

 bug, differ from this insect mainly in taxonomic characters rather 

 than in their bionomics. There are indications that occasionally a 

 nymph may molt only four times, as originally supposed, and very 

 rarely six times. This, however, is the exception rather than the rule, 

 and such variation is known to occur among larvse of various species 

 of lepidopterous insects. 



Table 3 



— Number and length of instars and total length of immature "period of 

 Blissus leucopterus, Columbia,. S. C, 1919-20. 



Cage No. 



Nymph emerged. 



Date of first molt. 



Length of 



first 



instar. 



Date of second molt. 



Length of 

 second 

 instar. 



1 19-450 



July 11 



July 27 



Bays. 

 16 

 16 

 11 

 9 

 9 

 17 

 10 

 11 



Aug. 2 



Bays. 

 6 



19-454 



Julv 11 



July 27 



July 31 



4 



19-459 



July 16 



July 27 



July 31 



4 



19-462 



July 9 



July 18 



July24 



6 



19-463 



July 10 



July 19 



July 26 



7 



19-466 



July 10 



July 27 



July 31 



4 



19-468 



July 10 



July 20 



July 27 7 



19-473 



July 16 



July 27 



Aue. 2 6 



19-476 





July 30 



13 Aug. 4 5 



19-478 



19-528 



2 20-700 



20-736 



July 17 



Julv 27 



10 July 31 ■.. 4 



July 26 





6 Ausr. 10 1 9 





June 29 



18 : July 5 6 





June 29 



14 July 5 6 



20-747 





June 29 



14 July 5 6 



14 July5 6 



20-748 





June29 



20-751 



June 12 



June 28 



16 Julv5 1 

















12.75 



5.75 











Cage No. 



Nymph 

 emerged. 



Date of 

 third 

 molt. 



Length of 

 third 

 instar. 



Date of 



fourth 

 molt. . 



Length of 

 fourth 

 instar. 



Date of fifth 



molt 



(adult). 



Le i£ of i.i5$h al of 



."!?_ immature 

 instar. period- 



119-450 

 19-454 

 19-459 

 19-462 

 19-463 

 19-466 

 19-468 

 19-473 

 19-476 

 19-478 

 19-528 



2 20-700 

 20-735 

 20-747 

 20-748 

 20-751 



July 11.... 

 July 11.... 

 July 16.... 

 July 9 

 Julv 10.... 

 Julv 10.... 

 July 10.... 

 Julv 16.... 

 July 17.... 

 Julv 17.... 



July 26 



June 11 



June 15 



June 15 



June 12 



Average. 



Aug. 10 



Aug. 9 



Aug. 9 



Aug. 2 

 Aug. 5 . 



Aug. 8 



Aug. 4 



Aug. 7 



Aug. 7 



Sept. 10... 

 July 12.... 

 July 17.... 

 July 10 .... 

 Julv 9 . 

 July 12 ... . 



Bays. 

 8 

 9 

 9 

 9 



10 

 8 

 8 

 7 

 3 

 7 



31 

 7 



12 

 5 

 4 

 7 



Sept. 5 

 Aug. 15. . .. 

 Aug. 19.... 



Aug. 13 



Aug. 15. ... 



Aug. 21 



Aug. 21 



Aug. 19 



Aug. 29 



Aug. 15 



Oct. 1 

 July 20 

 Aug. 8 

 July 26 

 Julv 19 

 July 29 



Bays. 

 26 



6 

 10 

 11 

 10 

 13 

 17 

 10 

 22 



8 

 21 



8 

 22 

 16 

 10 

 17 



Oct. 4 



Sept. 5 

 Sept. 17.... 

 Sept.-8 



Aug. 31 



Sent. 20.... 



Oct. 9 



Sept. 5 



Oct. 4 



Sept. 16.... 

 Oct. 28 



Aug. 3 



Aug. 29 



Aug. 5 



Aug. 11 



Aug. 14 



Bays. 

 29 

 21 

 29 

 26 

 16 

 30 

 49 

 17 

 36 

 32 

 27 

 14 

 21 

 10 

 23 

 16 



Bans. 

 ' 85 

 56 

 63 

 61 

 52 

 72 

 91 

 51 

 78 

 61 

 94 

 53 

 75 

 51 

 .".7 

 63 





9 



14. 12+ 



24. 56+ 66. 43 















» 19 refers to the year 1919. 



1 20 refers to the year 1920. 



