THE CANADIAN ENTOMOLOGIST 107 



few hours after the emergence of the adults. In one instance where careful 

 record was made of the time, the period was only one hour and five minutes. 



Where eggs are laid. — The spring adults with very few exceptions lay 

 their eggs in a chain-like arrangement along the main ribs or veins on the under 

 surface of the leaves, the leaves chosen being almost always situated in the 

 central, and lower part of the bush. Females of later generations are not so 

 particular where they lay their eggs and sometimes place them almost indis- 

 criminately over the leaves. This choosing in spring of the central part of the 

 plant for oviposition is from the standpoint of control an important matter; 

 because, when the eggs are hatched the young larvae feed on the leaves nearby, 

 eating at first little round holes in them and later devouring the whole leaf. 

 They continue to feed gregariously in the central part of the bush until they 

 are half grown, or even more. When the foliage is dense they have often eaten 

 most of the leaves in this part of the bush before any but a close observer would 

 notice that they are present. Accordingly, when they desert the central area 

 and disperse over the outer leaves, they quickly do a very great deal of damage 

 to the plant, especially as they feed ravenously and continue to eat all day 

 long. Hence the fruit grower who delays spraying until he sees the insects at 

 work on the outer leaves is likely to be late to kill them before they completely 

 strip his plants. 



Number of broods a year. — It is usually stated that there are only two 

 broods. Our experiments however, show that in 1919 there was a regular 

 spring brood followed by a partial second and a partial third brood, the latter 

 two over-lapping greatly. The second brood of larvae began to hatch from the 

 eggs about a week before red currants were ripe, and hatching continued for 

 fully a month. The third brood began to hatch a little more than two weeks 

 after the fruit ripened. Adults which produced this brood continued to emerge 

 in cages up into September. Fully half of the larvae from the first brood re- 

 mained in their cocoons throughout the year and did not transform into pupae 

 and adults to produce a second brood. The same thing was true of larvae of 

 the second brood. 



Fortunately the second and third broods appear to be of little importance, 

 for from some not clearly demonstrated reason, the great majority of the larvae 

 of these two broods died soon after hatching. Therefore, by destroying the 

 first brood but little fear may be felt from the second and third. 



Natural methods of control. — Two kinds of parasites were discovered, 

 one a Braconid and the other a Cynipid. In addition to this numerous larvae 

 and eggs were destroyed by Aphis lions and ladybird larvae. Another factor 

 in control is the heat of the soil, which destroys many larvae that fall upon it 

 accidentally or when seeking pupation quarters; and as mentioned above, large 

 numbers of larvae of the second brood for some unknown reason died soon after 

 hatching. In addition to this may be mentioned the fact that unfertilized 

 eggs produced only males. 



Artificial miethods of control. — There is scarcely any insect easier to 

 poison than this. We discovered that as small a quantity as one-half pound of 

 arsenate of lead paste in 40 gallons of water would kill small larvae. Our recom- 

 mendations are, however, to spray the bushes thoroughly with from one to 

 two pounds of arsenate of lead paste, or from one-half to one pound of arsenate 



