a 
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THE CLOUDY-WINGED WHITE FLY: LIFE HISTORY AND HABITS. 97 
TaBLE XXI.—Duration of pupal stage of cloudy-winged white fly. 





3 7 Sum of ; Sum of 
Speci- Num- Tia Speci- Num- ert 
teri Period of growth. ber of peranye men Period of growth. ber of pie tive 
No. dayee eens | aNo: dayae eeu 
v ture. ture. } 
| 
1 | May 24-June 11....:... 18 694 11 | Oct. 12—Mar. 27..-.... 167 3, 500 
2 |} May 26-June 14.......- 19 741 12°} Oct. 3i—Mar. 232. -...- 23 2, 893 
3) |) May: 26-July 19.5.2 25 2. 24 2,107 13 | Nov. 1—Mar. 25........ 145 2,920 
AMBIMaV DOr see Se nce lass eeretwenlicseeaee. | 14 | Nov. 14-May 29../.... 196 5, 102 
5 | July 161-Aug. 2....... 17 689 15 | Nov. 20-May 4........ 165 4,318 
6) | duly 18=Auge 5. c= 5.8 18 714 16 | Nov. 23-Mar. 28.....-. 125 2,981 
TARO. 9-OCta2G2s. 5225. - 17 466 © 17 | Dec. 3—Mar. 27.......- 114 2, 702 
8 | Oct..9-Oct. 28... . 22. - 18 519 18 | Dec. 3-Apr. 29........ 147 3, 662 
Shi Oct: S-Octy 30.4. ssa. 0 | 21 562 19 | Dec. 7—Mar. 28... ..... 111 2,681 | 
10s) Och -9-Oek, 265... 22-2 5 17 466 | 20 | Dec. 11—Mar. 24....... 104 2,476 | 



1Tt is to be regretted that the falling of the leaf upon which Nos. 5 and 6 matured prevented gathering 
data on the maximum length of stage at this season of year. 
GROWTH, MOLTS, LOCOMOTION, AND FEEDING HABITS. 
Concerning growth, molts, locomotion, and feeding habits, there is 
little to add to that already stated in connection with the larve and 
pupe of the citrus white fly. The two species are alike as regards 
the number of larval instars and in their crawling and sedentary 
habits. Their manner of feeding is similar also, with the exception 
that when crowded the larve of the cloudy-winged white fly settle 
freely upon the upper surfaces of shaded leaves, where they frequently 
reach maturity. 
MORTALITY AMONG LARV AND PUP. 
Remarks relating to mortality among the larve and pupe of the 
citrus white fly apply with greater force to the cloudy-winged white 
fly. This mortality appears to result from the same causes in the 
latter as in the former species. Life-history work has shown that 
mortality due to spring droughts and dropping from leaves is prac- 
tically the same for the two species, but that general mortality 
including ‘‘unexplained”’ mortality is about 3 per cent higher for 
A. nubifera. In this last respect, however, observations throughout 
groves where infestation is much heavier than on leaves used in the 
life-history work, and counts of forms on leaves infested with both 
species of fly, show that the comparative susceptibility to the influ- 
ences producing mortality of all kinds is often at least twenty times 
ereater for A. nubifera. This greater susceptibility appears to be 
due not only to the more delicate structure of the larvee and pups and 
their need of more room for development because of their larger size, 
but also to the adults’ habit of crowding the new growth with eggs 
far beyond its capacity for maturing the larve hatching therefrom. 
As may have been inferred already from statements upon the sub- 
ject of oviposition, it is this insatiable desire of the adults for feeding 
and ovipositing on new growth that is a most powerful factor lead- 
ing to the insect’s control. While a large amount of data might here 
86850°—Bull. 92—11——7 
