I N S KCT K N i: M 1 i:s f ) 1" Till': CODL I N ( -, MOTH. 249 



control (if this insect, there would always be certain years when 

 the host would dominate the parasite in numbers, a fact that is 

 true of every parasite and host, and the fruit-growers would 

 have lost enough in years of diminution of parasites to more than 

 ofi'set the expense that they would incur by spraying for this 

 insect. A'oz'ius cardinalis. in its relation to the control of 

 Icerya purchasi, is an exception to this rule. The fact that 

 Noz'ius cardinalis is so successful in the control of Icerya purchoM 

 is because the injurious effects of the Australian bug act slowly 

 on the host plant, and by the time that the several years of 

 dominance of the bug, necessary to do appreciable damage, have 

 elapsed, the parasite is again abundant. ' The codling larva, 

 however, produces immediate injury, and therefore requires more 

 immediate attention than a parasite will supj)ly. 



DESCRIPTIOX OF PLATE XX. 



Diagrammatic drawings of codling egg (a), much enlarged. The 

 egg'shell has been removed from those areas where the codling embryo 

 or parasites are developing. 



Fig. I ((j). — Appearance of codling egg (a) about 12 hours after it 

 lias been faid. 



1. Shell area, showing ridges and hexagonal areas. 



2. Cells of forming codling embryo. 



3. Red pigment beginning to appear. 



Fig. I (b), — Appearance of codling egg (a) February 13, three days. 



1. Codling egg-shell area. 



2. Developing codling embryo cells. 



3. Red pigment area. 



4. Egg of parasite under embryo cells. 



Fig. I (r). — Appearance of codling egg (a) February 14, 9 p.m., show- 

 ing 8 larvae of Chalcid parasite. 

 X. Codling egg-shell area. 

 1-8. Young Chalcid parasite larvae. 

 9. Red pigment surrounding Chalcid parasite larvae. 



Fig. I (d). — Appearance of codling egg (a) February 16, 9 p.m.. showing 

 apparent reduction in numbers of the Chalcid parasites. 

 X. Codling egg-shell area. 

 I. 3. 4. 5. 6, 8. Chalcid parasite larvs with black cell-like 



circular rings. 

 9. Remains of red pigment. 



Fig. I (c). — Appearance of codling egg (a) February 18, 9 p.m., showing 

 parasite larva* in prepupal stage. 

 -x. Codling egg-shell area. 

 I, 3. 4. 5. 6, 8. Chalcid parasites in prepupal stage. The 



characteristic larval form is lost. 

 The parasites are l)lack in colour, due to an accumulation of 



fine black granules. 



Fig. I ('/). — Appearance of codling egg (0) February 19. 9 p.m. 

 X. Codling egg-shell area. 



I. 3. 4, 5. 6, 8. Parasites in pupal stage. X'umber 3 shows 

 wings as well as other pupal characters. 



