22 BULLETIN 539, U. S. DEPARTMENT OP AGRICULTURE. 



LIFE CYCLE. 



The life cycles of the generations (Table IX) during summer are 

 considerably shorter than those of the fall of the year and possibly 

 shorter than that of the spring generation. The spring generation 

 has not been reared but probably has about the same cycle as the 

 fail generation. They are about as follows: 



Table X. — Duration of the spring and fall generations of Elasmopalpus lignosellus 



at Columbia, S. C. 



*iod or stage. " fi 



Time elapsing between emergence and oviposition. 



Egg stage 



Larval stage 



Pupal stage 



Total 



By comparing the two cycles it will be noticed that the time 

 required for the insect to pass through the cycle during the summer 

 months is only about 6.2 days more than one-half of the time required 

 in the fall of the year. 



NUMBER OF GENERATIONS. 



There are probably four generations of this species in the latitude 

 of Columbia, S. C, although it has not been reared continuously for 

 one whole year to verify this. However, three complete generations 

 were reared from the middle of June to the middle of October in 1913. 



Some of the pupae of the last generation gave rise to moths, while 

 the remainder died during the winter. Some of the larvae of. this 

 last generation, not pupating in the fall, died also during the winter, 

 apparently from the lack of suitable food and from being kept under 

 abnormal conditions. Otherwise they possibly would have com- 

 pleted their growth, pupated, and given rise to moths early in the fol- 

 lowing spring (1914). 



Our collection in the spring of 1915 would seem to substantiate 

 this. Larvae nearly full grown were found for the first time on corn 

 in the field during the first week in June, thus rendering it probable 

 that the eggs producing these larvae were placed when the corn was 

 up, by the moths issuing from pupae in the early spring, as the field 

 in which they were found was winter plowed and freed from rubbish 

 and grass, making it impossible for these larvae to have wintered 

 over under these conditions. 



