Summary A report is given on the occurence of mass outbreaks of Diprion species in Finland between 1897–1962. Diprion sertifer appears locally at intervals from 5–6 years; heavy outbreaks occured with approximately 30 years intervals in 1897, 1932–33 and 1960–62. D. pini shows usually localised outbreaks, scattered over the whole country. There exists in both species an ecologically and climatically well definid centre of outbreaks, which is of larger extension in D. sertifer than in D. pini.

The possible use of secondary genitalia (styles and spiculum ventrale) for the identification of females of Altica is investigated. Two identification keys are presented, one using both morphological and secondary genital characters and one using secondary genital characters only. The Finnish species are reviewed: A. cirsii Israelson is deleted, and A. quercetorum saliceti Weise and A. carduorum (Guerin-Meneville) are added to the Finnish list, now comprising 12 species. The geographical and temporal aspects of the distribution of the species in Finland is shown on UTM maps.

In experiments with breeding billets in Denmark, Sweden, and Finland, oviposition of the pine weevil Hylobius abietis L. started during May‐June and ended in August. Most eggs were laid during June and July. Pine weevils originating from eggs laid early in the summer developed according to a 2‐year generation pattern. The development of individuals hatched from eggs laid during July and later tended more and more to follow a 3‐year generation pattern. Zusammenfassung Der Zeitpunkt der Eiablage und sein Einfluß auf die Entwicklung von Hylobius abietis (L.) (Col., Curculionidae In Versuchen mit Brutknüppeln in Dänemark, Schweden und Finnland begann die Eiablage des Rüsselkäfers Hylobius abietis im Mai‐Juni und endete im August. Die meisten Eier wurden im Juni und Juli abgelegt. Rüsselkäfer aus Eiern, die früh im Sommer abgelegt worden waren, entwickelten sich entsprechend einer zweijährigen Generationsdauer. Die Entwicklung von Individuen aus Eiern, die im Juli und später abgelegt worden waren, folgte zunehmend dem Schema für dreijährige Generationsdauer.

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