1924 ENTOMOLOGICAL SOCIETY 45 



like loss, only one untreated field at Cote des Neiges, showing a loss of 9.9 per 

 cent., the highest observed in the vicinity. Sufficient has been seen, however, 

 to indicate that the use of cull or trap onions does offer a suitable base for 

 experimental studies of the future, and that in combination with a poison bait 

 liquid will probably prove the most satisfactory measures for control of the 

 onion maggot. 



NOTES ON THE LIFE HISTORY OF THE CLOVER LEAF WEEVIL 



(Hypera punctata) 



H. F. Hudson and A. A. Wood, Dominion Entomological Laboratory, 



Strathroy 



This paper is a very brief resume of the more important facts concerning the 

 life history of the clover leaf weevil as it occurs at Strathroy, Ontario. Clover 

 insects do not appear to have caused much damage in recent years in this locality. 

 This may be due to two causes; either the insects have not been sufficiently 

 abundant, or more likely, they have received little or no attention. 



The clover-leaf weevil would appear to be the major clover pest which has 

 come under our observation in recent years. Our first acquaintance with this 

 insect was in the spring of 1917, when several hundreds of acres of clover and 

 timothy meadows were severely injured in Delaware township. The depre- 

 dations of the larvae, however, did not last long, for a fungous disease broke out 

 which wiped out the entire infestation. Since that time they have again become 

 abundant. Among food plants, red and sweet clover appear to be favourite, with 

 some preference being shown for red clover. 



The beetles do not become sexually active until about the third week of 

 August. Eggs are deposited quite regularly until the middle of November, the 

 bulk of eggs being laid in September and October. Few, if any, beetles hibernate. 

 From the time the beetles emerge from the cocoon until sexual activity com- 

 mences, the beetles lead a very inactive existence, and feed sparingly. 



In our studies of the eggs over thirty pairs of beetles were used. The egg 

 capacity of the female varied from 34 eggs to 667 eggs. The female with a 

 record of 667 eggs oviposited over a period of 76 days with 46 days qf oviposition. 

 Other females laid 133, 240, 278, 324, 360 and 378 eggs, respectively. With 

 4,500 eggs under close study it was found that 55 per cent, were deposited within 

 the petiole of the clover plant, 27 per cent, in masses on the outside of the main 

 stem of the plant, and the balance on the soil surface or on the sides of the cage. 

 Under field conditions the percentage of eggs laid in the stems would have been 

 high, but in our experimental work young plants were used having no stems. In 

 a few cases wheat or oat stubble was introduced. Stubble was in all cases pre- 

 ferred for oviposition. Eggs laid in stubble had the highest percentage hatch, 

 due perhaps to the shrinkage of the green clover petioles removed with the eggs. 



The Egg. The egg period varies considerably. Those deposited during 

 the week of August 25th averaged 18.5 days, with the period lengthening out 

 until the week of September 22nd when the average was 31.3 days. The shortest 

 period obtained was 14 days, and the longest, aside from the over-wintering eggs, 

 was 42 days. A mass deposited November 10th hatched April 23rd. 



The freshly-laid egg is pale yellow. The shell is semi-transparent, and shows 

 the yolk indistinctly, the ends appearing watery and lighter in colour. A viscid 

 liquid is voided with the egg, by the female ovipositing. This liquid dries 



