8 BULLETIN 918, IT. S. DEPARTMENT OF AGRICULTURE. 



deposited on different parts of the plants, the results of which are 

 given in Table III. 



Table III. — Location on the cotton plant of the eggs of P. gossypiella. 









Number and location of eggs. 







Total 



Number of plants 

 examined. 



Leaves. 



Stems. 



Buds: 



Squares. 



Bolls. 



number 



of eggs 



on 





Bracts. 



Base. 



Tip. 



plant. 





7 

 32 

 21 

 94 

 31 

 20 

 22 



6 

 6 

 36 

 36 

 24 

 16 

 15 



45 

 107 

 34 

 66 

 37 

 56 

 17 



1 

 3 

 

 2 

 3 

 1 

 3 



8 

 11 



74 

 54 

 78 

 93 

 2 



81 

 108 

 87 

 53 

 49 

 55 

 39 





 3 

 

 1 

 1 

 2 

 



148 





270 





253 





315 





223 





243 





98 







Total (7 plants). 



227 

 14.7 



139 

 9.0 



362 

 23.4 



13 



0.8 



320 

 20.7 



472 

 30.5 



7 

 0.5 



1,549 







It is clearly seen that the boll is the most favored place, 51.7 

 per cent of the entire number of eggs being deposited on the, boll 

 and its appendages. The small leaf buds were second with 23.4 

 per cent, the leaves thud with 14.7 per cent, the stems fourth with 

 9 per cent, and the squares fifth with only 0.8 per cent. It is further 

 seen from this table that the base of the boll is frequently selected, 

 as 30.5 per cent of the eggs were deposited there and only 0.5 per 

 cent were deposited in the sutures at the tip of the boll. The 

 position of the eggs upon the plant is important, for upon it largely 

 depends the fate of the young larvae. It is essential that the larvae 

 reach the squares or bolls to feed, as no larvae were ever found which 

 had developed beyond the second instar on other parts of the plant. 

 It is a mistaken instinct of the moths to oviposit in other parts of 

 the plant, as it is evident that a much larger proportion of the larvae 

 hatching from eggs laid in close proximity to the food will reach it 

 than of those that have to crawl over the plant exposed to their 

 natural enemies in search of food. 



When laid on the leaves, buds, stems, and squares the eggs are 

 usually placed singly or in small groups of from 5 to 10. When 

 laid on the tip of the boll they are placed singly or in small groups 

 in the sutures. In this position the eggs are often flattened or 

 crushed by the growing of the boll. When laid at the base of the 

 boll they are placed between the calyx and the boll or beneath the 

 bracts around the base of the boll, and are usually in masses of 

 from a few to as many as 75 to 100, which are overlapped and 

 flattened out more or less shingle fashion. The flattened appear- 

 ance in this case is due to the presence of the calyx and not to the 

 natural shape of the egg. In these masses, eggs of all stages of 

 development, as well as shells, are found, showing that they were 

 not all deposited at one time by a single female. 



