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These observations on the piles of finely cut vegetable matter in the Javanesegilvus nests agree very well with those made byBathellier in Indochina, and besides, provide some useful additions to them. In many points they are also in agreement with the observations ofGrasse etNoirot for the African species. The main differences with the habits ofnatalensis in this respect appear to be that in the latter species the particles are piled up in the uppermotsts part of the habitaculum and are made into rather firm lumps, which are excavated afterwards. Therefore, the method of storing ofgilvus seems to bear a closer resemblance to that ofPseudacanthothermes.

Une recapitulation des descriptions anterieures sur la structure interne des constructions desMacrotermes spp. d'Asie (Haviland, 1898; Uichanco, 1919; John, 1926; Bathelier, 1927; Kemner, 1934; Pangga, 1936; Kalshoven, 1936; 1950) montre le caractere tres incomplet et insuffisant de nos connaissances dans la mesure ou elles traitent de ce sujet.

Pendant l'essaimage, les imagos ailes deNeotermes tectonae sont attires en grand nombre par les branches mortes ou les chicots des cimes des arbres de teck (Tectona grandis). Ces parties mortes, pour la plupart d'origine non pathologique, s'observent en abondance dans les plantations serrees, et elles restent attachees aux arbres longtemps, se decomposant peu a peu. Pour etablir leur loge, les imagos attaquent tres souvent la moelle exposee aux endroits ou une partie terminale s'est detachee, ou bien ils transpercent lateralement les branches pourrissantes. Ils n'utilisent que rarement d'anciens forages abandonnes. Les colonies primaires sont saprophages. Leurs galeries initiales suivent le fil du bois et sont tantot dirigees vers le sommet, tantot et le plus souvent vers la base des branches, ce qui s'explique peut-etre par le plus fort degre hygrometrique des parties basales. Ordinairement, les galeries des colonies juveniles s'etendent apres un ou deux ans dans les parties vivantes de la cime ou du tronc, mais les colonies peuvent subsister pendant trois ans et plus sur le bois mort, atteignant exceptionnellement dans ce milieu la phase de premiere apparition des individus ailes. On peut trouver jusqu'a six colonies primaires dans la meme branche. Bien qu'occupant la meme partie limitee d'un arbre et possedant des galeries entremelees, les colonies peuvent rester separees tres longtemps, du moins lorsque leur nombre n'excede pas deux. Les jeunes colonies vivent cote a cote avec d'autres especes d'insectes utilisant le bois pourri comme nourriture ou, tels que les fourmis, comme abri. Une fois etablies, les colonies paraissent ne subir que peu de pertes a la suite d'influences defavorables ou de predateurs; chose curieuse, elles ne sont pas recherchees par les pics.

A review is given of the recurrent outbreaks of the tentcaterpillar, Malacosoma neustria L., affecting the elm trees in the city of Amsterdam in the period 1930—1957. An outbreak of the brown tail moth, Euproctis chrysorrhoea L., in 1935—1936 is also mentioned and some occasional loss of foliage through the caterpillars of the vapourer moth, Orgyia antiqua L. Large fluctuations in the size of the Malacosoma populations were found. After some years in which the damage was negligeable, the increase always started in the N.W. part of the centre of the city. In the following years the outbreaks moved to adjacent parts of the centre and finally sometimes even to more eccentric parts (see Fig. 6—9). However, the occurrence of really harmful numbers of tentcaterpillars was mostly restricted to the centre of the town. The merits of the control measures which were carried out with derris/talcum powder spread by motordusters are discussed. The insecticide was thought to be the only sufficiently harmless for its use in the centre of a city. Some cases of defoliation and other inconveniences caused by the presence of crowds of caterpillars could apparently be reduced by the control measures. In several instances, however, the efficacy of the method remained doubtful. The urgency is stressed of further studies of the bionomics of Malacosoma under local conditions and some suggestions are made for a better organization of the measures applied.

A review is given of the recurrent outbreaks of the tentcaterpillar, Malacosoma neustria L., affecting the elm trees in the city of Amsterdam in the period 1930—1957. An outbreak of the brown tail moth, Euproctis chrysorrhoea L., in 1935—1936 is also mentioned and some occasional loss of foliage through the caterpillars of the vapourer moth, Orgyia antiqua L. Large fluctuations in the size of the Malacosoma populations were found. After some years in which the damage was negligeable, the increase always started in the N.W. part of the centre of the city. In the following years the outbreaks moved to adjacent parts of the centre and finally sometimes even to more eccentric parts (see Fig. 6—9). However, the occurrence of really harmful numbers of tentcaterpillars was mostly restricted to the centre of the town. The merits of the control measures which were carried out with derris/talcum powder spread by motordusters are discussed. The insecticide was thought to be the only sufficiently harmless for its use in the centre of a city. Some cases of defoliation and other inconveniences caused by the presence of crowds of caterpillars could apparently be reduced by the control measures. In several instances, however, the efficacy of the method remained doubtful. The urgency is stressed of further studies of the bionomics of Malacosoma under local conditions and some suggestions are made for a better organization of the measures applied.