117 



with this species either in 1914 or 1915 ; alate insects left the apple- 

 trees singly a day or two after becoming adults. No attenjpt was made 

 to determine the species of Graminaceae upon which the insect spends 

 the summer ; in experiments it lived readily on both oats and wheat. 

 The average number of young produced was 13, the length of life 

 averaging 27 days. The majority of the summer forms found on oats 

 are apterous, and congregate chiefly on the stema and lower portions 

 of the leaves. The apterous insects frequently wander from plant to 

 plant, though the summer migration is carried on mainly by alate 

 individuals. The immature stages of the summer apterous form 

 covered periods varying from 6 to 12 days, according to temperature 

 condit'ons. A chart illustrates the effect of temperature on the length 

 of the larval period. 



Apterous vivipara and autumn migrants are produced promis- 

 cuously, just as are the summer forms earlier in the season. Migration, 

 as with the spring forms, does not occur en masse but is distributed 

 over a period of 3 to 4 weeks, the insects collecting always on the leaves 

 and not on the twigs. The autumn migrants require 14 to 17 days, 

 or three or four days more than the apterous forms, to attain maturity ; 

 this may be due to the lower temperatures prevailing in the autumn. 

 An average of 6 young were produced by each female, the longevity 

 apparently being about 33 days. The insects hve for some days 

 after the reproductive period is over, as do the autumn migrants of 

 Anuraphis malifoliae, Fitch. 



The oviparous form matures very slowly in comparison with earlier 

 forms, requiring IG to 20 days to reach maturity. The males leave the 

 cummer host soon after becoming mature and fly to apple trees, where 

 they wait the appearance of the oviparous females. Mating usually 

 occurs on the twigs. The females may lay from 1 to 7 eggs and 

 generally die soon after depositing the last one. While the stem- 

 mothers and spring forms on apple prefer tender, succulent foliage 

 on which to feed, the ovipara need hard, matured leaves. 



Brain (C. K.). The Coccidae of South Africa.-IV.— 5i4L Entom. 

 Research, London, x, no. 2, January 1920, pp. 95-128, 8 plates. 



The genera dealt with in this paper, which is the fourth of the 

 series [R.A.E., A, iv, 134 ; vii, 138, 242] are Chionaspis (continued), 

 Lepidosa plies, Ischnaspis, Asterolecanium, Lecaniodiaspis, Cerococcus, 

 Tachardia, Hah'mococcus and a new genus, Baccacoccus. 



The new species described are :— Chionaspis scutiae, on Scutia 

 indica ; C. cajfra on Acacia sp. ; C. ambiguus on Hlac ; C. leucadendri 

 on Leucadendron argenteum ; G. (Pkenacaspis) launsburyi var. eJce- 

 bergiae, n., on Ekebergia sp. ; C. (Dinaspis) imbricafa on Euclea 

 nalalensis ; C. (D.) diosmae on Diosrna crenata ; Asterolecanium 

 brevispinum on veld bush ; A. borboniae on leaves of gorse {Borbonia 

 cordata) ; A. conspicuum on Acacia spp. ; A. stentae on Caralluma 

 caudata, Huernia transvaalensis and Siapelia sp. ; Lecaniodiaspis 

 natalensis on Hibiscus ; L. magna on a native bush ; Ij. brabei on 

 wild almond {Brabeivm stellatifolium) ; Cerococcus passerimie on 

 Passerina ericoides ; C. royetiae on Royena pallens ; Tachardia minor 

 *ind T. karroo on Elytropappus rhinocerotis ; T. affluens on Euclea 



