482 



MRS. O. A. MERRirr HAWKJiS ON THE 



The average number of eggs laid was between 140 and 148, the 

 largest numbers laid were 167 in 1918, 189 in 1919, and 418 

 in 1920. The largest number laid in twenty-four hours v/as 80. 

 The Black and Red forms are not differentiated by the colour, 

 size, or shape of the eggs or by the number of eggs laid. 

 Clausen (3) found 190 the average number laid in America. 



The eggs are usually laid on the under side of leaves, but may 

 also be found in slight depressions on the trunk and branches ; 

 on the trunk they are usually on tlie north side or at the angle 

 where a branch originates. The bright-coloured eggs are very 

 conspicuous on the brown bark. On the lower three feet of the 

 trunk of a plum-tree badly attacked by aphis, I found within a 

 week 42 patclies of Coccinellid eggs — A. hipitnctata, II. lA-giUtata, 

 II. l4:-punctata, C. ll-punctata, and C. variabilis. Evidently 

 there is a tendency to lay the eggs away from the light, but I 

 have watched a septeiupicnctata lay her eggs on a stone in bright 

 sunlight. The usual period of incubation is three days, but it 

 may extend to nine. The average laying period of tlie first two 

 years' observations was 24 days. Incubation varied from 3 to 13 

 days, the average being 5 days in 1918, 4 in 1919, and 7| in 1920. 

 Clausen (United States) finds the average incubation 5 days and 

 the average egg-laying 28'2 days. 



c. The Larvce. 



The larvie when about to pupate are of a blackish-brown colour. 

 The first upper lateral abdominal tubercle is always orange, and 

 an orange patch extends across the abdomen between the fourth 

 dorsal abdominal tubercles. This orange patch may be succeeded 

 by similar patclies of decreasing size and colour-intensity in the 

 5th, 6th, and 7th abdominal segments. In many cases there may 

 be orange on the lower lateral tubercles of the fourth abdominal 

 segment. The lower lateral tubercles may be surrounded by a. 

 cream-coloured ring (see note to Table I.). There is great varia- 

 tion in the depth of colour of the orange patclies. 



I have made many unsuccessful attempts to determine the 

 differences in the larvje and pupie which are destined to become 

 respectively Ked and Black imagines. In 1918 the average larval 

 period was 27 days, the minimum 22 and the maximum 27. In 



1919 the average was 23, the minimum 16 and the maximum 39. 

 Clausen found the average 16"1 days for the United States. In 



1920 the average larval period was 35 days, the minimum 23, 

 and the maximum 37. 



d. The rupee. 



The larvae usually pupate on the underside of leaves, especially 

 where the edge is curled up by aphis or drought. Pupae are 

 sometimes found on the upper side. In 1918 very few pup?e were 

 found on the upper side of leaves, but in the early part of 1919, 



