LIFE-IIISTORY OF THE LADY-BIltD BEETLE. 



481 



male and female are isolated in a box, mating takes place at 

 intervals during a period of two to nine weeks. Copulation lasts 

 from half to three-quarters of an hour. It takes place when no 

 eggs are laid and when the egg-laying period of the female is 

 finished. Palmer states that the female lays fertile eggs three 

 weeks after fertilization. Mating takes place in Staffordshire 

 and Warwickshire during the whole summer, but the principal 

 season is May to June, with a subsidiary season from the middle 

 to the end of August. Probably only a very few of the newly 

 emerged Lady-birds breed until the following year. The insects 

 have been found mating on sunny days in late September, but at 

 that time no eggs were laid. 



b. The Eggs. 



Dates of 

 Ovipositioii 



(1) 

 (2) 

 (3) 

 (4) 

 (5) 

 (6) 



22. 7. 



22. 7. 



23. 7. 

 27. 7. 

 27. 7. 

 27. 7. 



(7) 28. 7. 



(8) 29. 7. 



(9) 1. 8. 



(10) 3. 8. 



(11) 7. 8. 



(12) 9. 8. 



Table I. 



Detailed Record of Family, 33 (1919). 



Number of Eggs 

 and Colour. 



16 (yellow) ") 



24 (orange) ] 



8 (deep orange). 

 8( „ „ ). 



11 ( „ „ \ 

 3 (yellow base, 



orange ti])). 

 21 (orange). 



25 (yellow base, 



orange tip). 

 25 (dee]) orange). 

 24 ( „ ). 



12 ( „ ). 



8( „ „ ). 



Total 18£ 



Incubation. 

 (Days.) 



Av. 5-6 



Larval life. 

 (Days.) 



16 



Av. 20-2 



Pupation. 

 (Days.) 



Av. 8-2 



Number of 

 Imagines. 



Total 24 



Mating took place on 17.7.19 between two Red " ty\)c'^ Adcdias. In batclies (1) 

 and (8) tbe larvae bad ligbt rings around all tlie abdominal and tboracic 

 tubercles : lience these larva? appeared much lighter than the larva? of the 

 remaining batches, which only had light rings around the lower lateral 

 tubercles. The resulting imagines were all red, those from these two batches 

 being indistinguishable from the others. 



The eggs are spindle-shaped and laid in batches of from three 

 to fifty. The outer shell is colourless and covered w^ith numerous 

 protuberances. The colour of the egg is due to the yolk, which 

 is usually yellow but may be orange — a range of shades similar 

 to those of the yolk of the hen's egg. Usually the whole batch of 

 eggs laid on a single occasion is of the same uniform colour, but 

 they may vary (see Table I.). In several batches the eggs shaded 

 from yellow at one end to orange at tlie other. The eggs do not 

 change in colour until a few hours before the larvpe are to 

 merge, when they become a greenish grey. 



