58 



BULLETIN 416, U. S. DEPARTMENT OF AGEICULTUEE. 



9-spotted lady-beetle (fig. 19) is probably most abundant. Its sea- 

 sonal occurrence doubtless corresponds very closely with that of H. 



convergens, although our 

 records of the latter have 

 usually been somewhat 

 earlier. 



One adult individual from 

 infested cotton ate 31 adult 

 red spiders in 24 hours. 

 Occasional observations 

 have been recorded of this 



T-iG. 19.-The niiie-spotted lady-beetle {Coccinella novemno- COCCmellld lecdmg On red 

 tala), an enemy of the red spider: Larva at left, adult at spidcrS in the field. At 

 right. Much enlarged. (Chittenden.) Batcsburg the OUe rCCOrd 



for incuJ)ation was 3 days (in August) and for the pupal period the 

 solitary record occupied the last 10 days of August. 



LEPIDOPTERA. 



NOCTUIDAE . 



Alabama argiUacea Htibn. — When the cotton leafworm caterpil- 

 lars become abundant, usually in late September or early October, 

 they devour every vestige of the 

 cotton foliage, excepting the 

 stalks, branches, and petioles. 

 Consequetitly myriads of red 

 spiders which are harbored on the 

 leaves at the time of defoliation 

 are eaten along with the leaf tissue. 

 In this way the leafworm acts most 

 effectively as a remedial agency 

 against the mites. There is an addi- 

 tional consideration in this con- 

 nection, namely, that those mites 

 which are not actuahy devoured at 

 the time of the defoliation are com- 

 pelled to seek new hosts through 

 migration. 



Fig. 20. — Knapsack sprayer suitable for spraying 

 low-growins plants. (Quaintance.) 



APICAL SWARMING. 



At times of continued drought and heat the lower and earher 

 infested leaves of many plants become dry and unattractive to the 

 red spiders, which travel upward or outward, seeking the apical 

 leaves, that normally remain green longer. If the plant is heavily 

 infested, a swarming horde of mites is often witnessed converging 

 toward and concentrating at the apices of the branchlets. Upon 



