Some interesting revelations about the nest of Polistes hebroeus Fabr. (Vespidae, Hymenoptera) -- the common yellow wasp of India.

Nest building at the end of winter in Pobstes hebroeus, is dependent on the suitability of the site and its height from the ground level. Healthy wood fibres are used as material for the construction of cells which is done in instalments. No two queens will ever agree to work together with the result that some nests, at the very inception meet their ill fate. The largest nest is 2ft. 7½ ins. in circumference with 1456 cells. Imagines only hibernate. Unemerged individuals die during autumn disaster. Preimaginal stages are differentiable on structural characters. Prepupa is not divisible into two substages

The Life-History in the Field and the Anatomy of fully-grown Larva of Doliphoceras pseudococci Alam, an Endoparasite of Pseudococcus newsteadi Green (Hymenoptera: Encyrtidae & Hemiptera: Coccidae).

Beschrieben werden Lebenszyklus von Doliphoceras pseudococci Alam, Morphologie und Anatomie der Larve und die Bedeutung als Parasit von Pseudococcus newsteadi Green. Die Verwandtschaft von Thomsonisca und Doliphoceras wird auf Grund der Ähnlichkeit der Kopfkapsel erörtert. Ein höherer Entwicklungsstand der Encyrtiden gegenüber den Braconiden wird auf Grund des Atmungs- und Nervensystems vermutet.Doliphoceras pseudococci Alam is an endoparasite of Pseudococcus newsteadi Green. The latter is a well known pest of Fagus sylvatica L. Both the host and the parasite has one generation a year with their different stages well adjusted to bring about stable hostparasite relationship. The latter has some significant features which suggest utilization of D. pseudococci in the biological control of P. newsteadi. As many as five larvae are found developing in one host. The larvae gradually get enclosed in separate membranous envelopes which, later on, dry up to form rigid chambers for pupation. The larval anatomy incorporates both the external and internal structures. The presence of distinct similarity in the head capsules of Thomsonisca britanica Alam and Doliphoceras pseudococci Alam suggests probable close relationship of the two genera. The tenth segment possesses a pair of lateral processes. The structure of the head capsule supported by the nature of the respiratory and nervous systems suggests a higher evolutionary status to Encyrtidae over Braconidae

Undescribed Encyrtid Parasites of Homopterous Insects (Hymenoptera: Chalcidoidea).

Zwei neue in Homopteren parasitierende Encyrtiden werden beschrieben: Aphidencyrtus qadrii und Blastothrix coryli. Bestimmungsschlüssel für die Weibchen der Gattungen Aphidencyrtus und Blastothrix werden beigegeben.Nomenklatorische Handlungenqadrii Mashhood Alam, 1961 (Aphidencyrtus), spec. n.coryli Mashhood Alam, 1961 (Blastothrix), spec. n.There are described as new Aphidencyrtus qadrii and Blastothrix coryli, encyrtid parasites of Homoptera. Revised keys to species of Aphidencyrtus and Blastothrix females are included.Nomenclatural Actsqadrii Mashhood Alam, 1961 (Aphidencyrtus), spec. n.coryli Mashhood Alam, 1961 (Blastothrix), spec. n

Solvent selection for fabrication of low temperature ZnO electron transport layer in perovskite solar cells

Zinc Oxide (ZnO) with an easy synthesis method, low processing temperature, and high charge carrier mobility has been considered as a proper electron transport layer (ETL) for perovskite solar cells. Herein, we investigate the effect of the most common solvents for the preparation of ZnO and investigate their application as ETL for PSC. ZnO layers were prepared from three different solvents 2-methoxyethanol (2ME), isopropyl alcohol (IPA) and ethanol. A complete investigation of the structural, morphological, optical and device performance was performed. The results show that the type of solvent has a significant effect on electrical, optical and structural properties of ZnO layer, the capping perovskite layer composed of methyl ammonium lead iodide (MAPbI3) and the total performance of the cell. The ZnO film prepared by 2ME as the solvent showed the best performance mainly because of better surface coverage by MAPbI3, larger grain sizes, fewer pinholes, satisfying the Pb/I theoretical stoichiometry in the perovskite layer and the highest absorbance compared to other solvents. In addition, the simulation modeling shows that the ZnO (2ME)/MAPbI3 interface has the lowest defect density and for having planar ZnO-based PSCs with PCE of over 22%, the interface defects should be kept under 10(13) cm(-3)

The investigation of the unseen interrelationship of grain size, ionic defects, device physics and performance of perovskite solar cells

Controlling the phenomenological morphology effects on the performance of the perovskite solar cell (PSC) is a continuing concern due to its photo-physical complexity and the existing contrary reports. Distinguishing the effect of the formed electron and hole traps in the bulk and at surface/interfaces of the perovskite layer from their impact on the performance of the device can be beneficial in optimizing fabrication methods. Here, the transient AC and steady state DC measurements, and morphology characterizations confirm the variation of performance parameters with respect to grain boundaries growth. The device physics is uncovered with respect to the grain size (GS) of the perovskite layer employing the theoretical drift-diffusion framework incorporating the electronic and ionic contributions. The increase of open circuit voltage (V-oc) for devices with large GS can be associated to the density of defect states. The findings here suggest a more pronounced role of interfaces in efficiency enhancement of the PSCs with the emphasis on the impact of the hole transport layer (HTL)/perovskite layer interface which is also found to be accountable to the difference between the device internal voltage and the terminal voltage and minimizing this difference can lead to an enhancement of approximately 100 mV in V-oc. Additionally, the electron traps in the bulk of the perovskite layer play a distinguishable role in the reduction of V-oc for the device with the smallest GS. The ionic defect density is also estimated. Considering our results and previous reports, the performance of the PSC is remarkably dependent on the method of fabrication and the associated perovskite conversion mechanism, and not necessarily on GS. The results are expected to deliver important guidelines for the development of more efficient PSCs by further enhancement of the V-oc towards its thermodynamic limit of 1.32V, via creating optimal interfaces