340 



history of 5. oleae. The scale, in Cahfornia, has two distinct types of 

 development, the even hatch, when development is characterised by 

 a uniform generation of black scale, and uneven hatch, when the scale 

 is found in all stages at any season of the year. A chart shows the 

 relative development of the black scale and its parasite. Under the 

 former type of development the parasites are active from February 

 to July. By July all the parent scales are dead, and only the young 

 ones survive. These are too small to serve as a host for the parasite 

 until after the second moult, in the following February ; consequently 

 there are six months when there is no available host for the parasite. 

 It is obvious that, under these conditions, heavy liberations of 

 parasites must be made as soon as the scales become vulnerable, 

 especially as the effectiveness of the parasite depends upon the number 

 of generations it can produce to one generation of the scale. These 

 conditions of even hatch, moreover, occur over the greater part of the 

 citrus regions of southern California. The problem is therefore to 

 discover an economical method of rearing large numbers of the parasites 

 for liberation at the opportune moment each year, since they cannot 

 maintain life in the citrus orchards in any numbers from year to year. 

 A method that shows considerable promise is the production of potato 

 sprouts in individual containers and the stocking of these with scales, 

 parasitising them with A . lounshuryi, and then distributing the sprouts 

 in the orchards ; this eliminates any handling of the individual 

 parasites. Citrus or pepper-tree cuttings infested with scale can be 

 similarly parasitised and returned to the orchards. It is thought 

 that this method will prove far more economical than fumigation. 



A further problem that requires attention is the eradication of the 

 Argentine ant [Iridomyrmex kmnilis] from the orchards; this must 

 be accomplished before the best results can be obtained from the use 

 of natural enemies. 



EssiG (E. O.). Some interesting Economic Insects recently observed 

 in California. — Mthlv. Bull. Cal. Dept. Agric, Sacramento, x, 

 no. 4, April 1921, pp. 140-143, 3 figs. 



Spermophagus pectoralis, Sharp (Mexican bean weevil) is somewhat 

 similar to Bnichus (Acanihoscelides) oUectus, Say (bean w'eevil) in 

 appearance and habits of infesting stored beans, but is perhaps more 

 destructive, as it breeds in great numbers throughout the year. A 

 Hymenopterous parasite of it has been reared. Ceroplasies cirripedi- 

 formis, Comst. (barnacle scale), usually a greenhouse pest, has recently 

 been taken in citrus orchards. C/irysomphalits dictyospermi, Morg., 

 one of the most serious scale-insects attacking Citrus in Spain, has been, 

 taken on ornamental palms, chiefly Kentia spp. in greenhouses, and 

 has caused the death of young avocado trees. The Nitidulid, 

 Carpophilus dimidiatus, F., frequently occurs on sour and deca^dng 

 fruit in southern California, and in the flowers of Opuntia spp. It 

 has recently been found infesting shelled peanuts from Java, in company 

 with Tenebroides mauritanicus, L. (cadelle), Tribolium castaneum, 

 Hbst. (red flour-beetle), Silvamis surinamensis, L. (saw-toothed grain 

 beetle), and Plodia inter punctella, Hb. (Indian meal-moth). Another 

 moth, Aphomia gularis, L., has been taken in shelled peanuts from 

 China. Lasioderma serricorne, F. (cigarette beetle) has adapted itself 

 to copra and copra cake, which it is seriously infesting. Other insects 

 taken on copra are 5. surinamensis, T. castaneum, and Necrobict 

 rufipes, F. 



