364 



adults or June beetles do much damage to the fohage of trees and 

 shrubs. 



L. anxia appears in the adult form in mid-May, about the 

 time when willows and aspens are bursting into leaf. Eggs are 

 generally laid in June, being deposited singly in small cavities at a 

 depth of 1 to 4 inches. This species prefers rich soils or lowlands, 

 such as river flats. The larvae live chiefly on decayed vegetation 

 for the first season ; during their second summer they are only destruc- 

 tive if very numerous. During the third season the insect feeds on 

 hving roots and may damage many kinds of crops. By June of the 

 third year the larva is generally mature and pupates close to where 

 it has been feeding. The adults generally remain in the pupal chamber 

 until the time of emergence in the following spring. The life-histories 

 of the other species differ from that of L. anxia only in certain 

 particulars. L. nitida appears rather later than L. anxia, and generally 

 prefers a drier soil ; the adults seldom. leave the open groves where 

 they breed. Aspens are apparently the favourite food, though elm& 

 also are attacked. L. drakii is the largest species found in Manitoba ; 

 the beetles appear towards the end of August, their chief food consisting 

 of aspens and oak. L. rugosa is by far the most abundant 

 species on sandy soils. Beetles emerge soon after the trees come 

 into leaf, their food-plants being apple, plum, wild cherry, thorn, 

 rose, elm, maple, oak and aspen, especially the last-named. Eggs 

 are found at depths varying from 1 to 7 inches and hatch in late July 

 and early August. 



White grubs pass the winter at varying depths beneath the soil 

 surface ; the larva of L. anxia hibernates at a depth of 44 in. in dry 

 woods and from 14 to 25 in. in wet situations. The average depth 

 for L. nitida is 34 inches, for L. rugosa 74 inches and for L. drakii 

 about 40 inches. In some species the adult beetles, as well as the larvae, 

 burrow down into the soil in winter. While the other Manitoba species 

 remain in the pupal chamber or burrow shghtly below it, L. rugosa 

 begins to burrow soon after the beetles mature, that is about 1st 

 September, and by the approach of winter is found at an average 

 of 29^ in. below the soil surface. 



As a control measure, ploughing should be done between 14th May 

 and 1st July, to an average depth of 5 in., in order to expose the 

 maximum number of grubs, eggs or pupae. The majority will 

 probably be devoured by birds, but for the remainder the ground 

 should be harrowed soon after ploughing so that the egg-cells may 

 be broken. Wheat should not be sown upon such ground, but winter 

 rye may be sown, followed by oats. Natural enemies of Lachnosterna 

 include robins, blackbirds, cow-birds {Molothrus ater), and, above 

 all, crows, which follow the plough eagerly in search of the exposed 

 grubs. Many animals eat white grubs, including the skunk, which 

 more than compensates for its occasional destructiveness to hens' 

 eggs, etc. by digging up the grubs, which it can detect by scent ; 

 other animal enemies are badgers, shrews and field mice. Insect 

 parasites reared in Manitoba include the Tachinids, Cryptomeigenia 

 thelitis, Wlk., which destroyed about 50 per cent, of the beetles in 

 1914, and Microphthalma disjuncta, Wied. ; the Dexiids, Ptilodexia 

 abdominalis, Desv., and P. tibialis, Desv. ; Myiocera cremiodes, 

 Wlk., (?) has also been found in the grubs. A mite, Tyroglyphus 



