14 THE REPORT OF THE No. 33 



The above dates are the earliest recorded for each stage, the averages being 

 from one to two weeks later. The period of emergence for the adult may be 

 especially prolonged in some cases; certain apparently healthy larvae, after 

 hibernating, having failed to pupate as late as the next September. It would 

 seem, therefore, that, as an additional means of preservation of the species, some 

 individual members may hibernate for a second time. 



Plants Attacked. All of our native roses as well as various cultivated 

 ones, such as Rosa rugosa, are attacked by the Curculio. While none appear to 

 be immune there is yet a marked difference in the degree to which plants are 

 infested, the location as well as varietal susceptibility causing variations. 



Thus in early September larvae have been found in as many as 63.3 per cent, 

 of the hips of R. pratincola on an open southern slope, while along a roadside in 

 Bottineau county, N.D., R. pratincola was found infested to as high as 74 per 

 cent. In the case of plants partially protected by trees the percentages were 

 distinctly lower, probably because of the preference of the insect for bright 

 sunshine. At the edge of a wood R. acicularis and R. blanda have been found 

 infested to the extent of 29.6 per cent., while for plants entirely shaded within 

 the wood, 6 per cent, was the highest for any species. The relative susceptibility 

 of R. macounii has not been determined because of its rareness in Manitoba. 

 Injury to small fruits such as blackberries and raspberries, as mentioned by 

 some observers, has up to the present been negligible here. 



Natural History and Habits. In southern Manitoba the first adults 

 appear promptly about June 1st and are most abundant by the middle of the 

 month. They disappear rather suddenly in July but specimens have been seen 

 by us as late as August 7th, this being due, as has been mentioned, to the late 

 pupation of some of the larvae. 



Upon emerging, the Curculio ascends a convenient rosebush and, after 

 sunning for a while, begins to feed on the buds by making deep punctures with 

 its well-adapted beak, often eating twenty or more holes in the same bud and 

 sometimes a few additional ones in the hip. When not feeding it rests upon the 

 foliage a great deal, but on bright, warm mornings it is never idle. Copulation 

 is common a few days later and egg-laying begins towards the end of June. 



The eggs are laid in the punctures and are inserted sufficiently to be almost 

 concealed. Only one, or more rarely two eggs, are laid in each bud. 



Hatching commences the second week in July and the young larvae live for 

 a short time within the flowers, then desert the flowers for the hips where they 

 are found the latter part of August feeding on the seeds. Here they develop 

 rapidly. Only one fully developed larva has been found to survive in each hip. 

 Beginning about September 4th, the larvae bore their way out of the hips, fall to 

 the ground and bury themselves to a depth of 1^ to 4 inches in the soil where 

 they hibernate. By the middle of the following May the first pupae are being 

 formed in the soil and, after a period of two weeks, the first adult Curculio 

 emerges. 



Egg. Pale yellow, shiny, somewhat translucent, distinctly narrower at one 

 end than the other and varying a little in size. Length: 0.9-1.2 mm.; width: 

 0.6-0.9 mm. 



Larva. Colour pale yellowish, except the portion of the head above the 

 epistoma, which is dark-brownish, the coloration extending farther along the 

 mid-line; clypeus and labrum pale; mandibles black with three teeth; antennae 

 one-jointed and situated at the bases of the mandibles, slightly darker than the 



