ECONOMIC ZOOLOGY ENTOMOLOGY. 263 



judging from these very unsatisfactory data, about days would be required 

 for the beetles to become fully mature. . . . When ready to oviposit, the female 

 works her way down into the soil until she reaches the moist layer, where she 

 lays her quota of eggs. . . . Beetles captured in copula and confined in vials 

 laid from 4 to IS eggs." 



The ongovity of the beetle is said to be quite variable, several lots of newly 

 emerged insects dying within a week, while an individual from a lot collected 

 ^Lay 11 lived until August 22. From 3 to 6 weeks is thought to be the average. 

 Any soil with a moderate moisture content appears to be favorable for the 

 growth of the larvae, the texture having no influence whatever upon them. 



The species has been observed feeding ujion a large number of plants. Labo- 

 ratory experiments showed a difference in the food ])lants preferred by beetles 

 captured on hops and those collected from mangels. " During the spring and 

 early summer the beetles fed upon the shoots and tendei- buds and ate holes 

 the size of a pin head in the leaves. ... In feeding ui»on the hop plants, the 

 beetles dug small i)its in the shoots, which when the attack was severe caused 

 the death of the stem. In the fall the beetles climb the trellis poles and ci-awl 

 along the vines until they reach the hoi) cones, of which they are very fond. 

 When the beetles appear in large numbers they will devour a plant com- 

 pletely." 



There are two distinct Itroods of beetles in the Chilliwack and Agassiz valleys. 

 One emerges in the early spring and the otlier in the latter part of July or 

 the first part of August. About .S4 days is said to be required for the comple- 

 tion of the life cycle. Hibernation connnences with the arrival of cold 

 weather, the beetles crawling into the first favorable place that is found. In 

 1909 the first beetles observed emerged March 9. The maximum number, how- 

 ever, did not appear until April 15. 



Beetles collected between June 10 and 14 are said to have I)een killed in 

 large numbers by a bacterial disease. " The larva of one of the Carabidse was 

 quite plentiful in the soil, and under laboratory conditions was observed to 

 feed voraciously upon the flea-beetle larvre. Two species of centipedes were 

 also numerous, but oidy one was observed feeding upon the larvae. 



Control measures are considered under the headings of tarred board or sticky 

 shield, tarred sledges, banding with tanglefoot, destruction of hibernating bee- 

 tles, Boi-deaux mixture, Bordeaux-tobacco extract, tobacco dust, impractical 

 measures, sju-aying, traits, and cultivation and fertilization. These measures 

 were tested during the spring and summer, the apiilication of tanglefoot and 

 under some conditions the use of the sticky shield proving to be the key to the 

 flea-beetle problem. At the time the vines are ready to train, the beetles may 

 l>e greatly reduced in numbers so that the vines can reach the strings by the use 

 of the sticky shield or the heavier tarred board. "After the vines are trained 

 the beetles are readily controlled by the use of tanglefoot bands. These bands 

 should be renewed on the vines, and the trellis poles should also be banded at 

 the time that the vines are tied in and stripped, or just before the appearance of 

 the second generation. These tanglefoot bands form a perfect barrier to the 

 insects. Even though the beetles are present in very large numbers they can 

 not reach the upper parts of the hop vines, which can therefore i)roduce a crop 

 without molestation. In order to starve the beetles the yards should be well 

 <Mltivated and all suckers cut from the bases of the vines. If this is done the 

 emerging insects will find very little to feed upon. In some cases the destruction 

 of the beetles which hibernate in the trellis poles, string pegs, and vine stubs 

 may be advisable, but if the banding is thoroughly done and the yards are kept 

 clean during the growing season, very few beetles will live through the winter 

 to attack the vines in the following spring." 



