The fast-running flies (Diptera, Hybotidae, Tachydromiinae) of Singapore and adjacent regions

This is the first comprehensive introduction to the flies of the subfamily Tachydromiinae (Hybotidae) of Singapore. The monograph summarizes all publications on the Tachydromiinae of Singapore and includes new data resulting from mass-trapping surveys made in Singapore during the last six years. A few samples from Malaysia (Johor province, Pulau Tioman and Langkawi) have been also included in this study. In Singapore the Tachydromiinae are the most diverse group of Empidoidea (except Dolichopodidae) and currently comprise 85 species belonging to the following nine genera: Platypalpus (1), Tachydromia (1), Chersodromia (6), Pontodromia (1), Drapetis (5), Elaphropeza (60), Crossopalpus (1), Nanodromia (3) and Stilpon (7). All species are diagnosed and illustrated. The following 28 species are described as new for science: Chersodromia bulohensis sp. nov. (Singapore), C. glandula sp. nov. (Singapore, Malaysia), C. malaysiana sp. nov. (Singapore, Malaysia), C. pasir sp. nov. (Malaysia), C. sylvicola sp. nov. (Singapore), C. tiomanensis sp. nov. (Malaysia), Crossopalpus temasek sp. nov. (Singapore), Drapetis bakau sp. nov. (Singapore, Malaysia), D. hutan sp. nov. (Singapore), D. laut sp. nov. (Singapore, Malaysia), D. mandai sp. nov. (Singapore), D. pantai sp. nov. (Singapore, Malaysia), Elaphropeza chanae sp. nov. (Singapore), E. collini sp. nov. (Singapore), E. gohae sp. nov. (Singapore), E. kranjiensis sp. nov. (Singapore), E. lowi sp. nov. (Singapore), E. semakau sp. nov. (Singapore), E. shufenae sp. nov. (Singapore), Nanodromia hutan sp. nov. (Singapore), N. spinulosa sp. nov. (Singapore), Platypalpus singaporensis sp. nov. (Singapore), Pontodromia pantai sp. nov. (Singapore), Stilpon arcuatum sp. nov. (Singapore), S. neesoonensis sp. nov. (Singapore), S. nigripennis sp. nov. (Singapore), S. singaporensis sp. nov. (Singapore), S. weilingae sp. nov. (Singapore). A redescription is given for Crossopalpus exul (Osten-Sacken, 1882) (Taiwan). Males of Elaphropeza feminata Shamshev & Grootaert, 2007 and E. modesta Shamshev & Grootaert, 2007 as well as females of Elaphropeza ubinensis Shamshev & Grootaert, 2007 and Nanodromia narmkroi Grootaert & Shamshev, 2003 are described for the first time. Keys to genera and species, which are generally applicable to the whole of Southeast Asia, are compiled. An analysis of the species ecological preferenda is presented

On the robustness of herds

Herd behavior is argued by many to be present in many markets. Existing models of such behavior have been subjected to two apparently devastating critiques. The continuous investment critique is that in the basic model herds disappear if simple zero-one investment decisions are replaced by the more appealing assumption that investment decisions are continuous. The price critique is that herds disappear if, as seems natural, other investors can observe asset market prices. We argue that neither critique is devastating. We show that once we replace the unappealing exogenous timing assumption of the early models that investors move in a pre-specified order by a more appealing endogenous timing assumption that investors can move whenever they choose then herds reappear.Investments ; Econometric models

Reply to Solow

Here we reply to Robert Solow’s comment (forthcoming) on our work (Chari and Kehoe (2007)).Macroeconomics

Financial Crises as Herds: Overturning the Critiques

Financial crises are widely argued to be due to herd behavior. Yet recently developed models of herd behavior have been subjected to two critiques which seem to make them inapplicable to financial crises. Herds disappear from these models if two of their unappealing assumptions are modified: if their zero-one investment decisions are made continuous and if their investors are allowed to trade assets with market-determined prices. However, both critiques are overturned---herds reappear in these models---once another of their unappealing assumptions is modified: if, instead of moving in a prespecified order, investors can move whenever they choose.

The heterogeneous state of modern macroeconomics: a reply to Solow

Robert Solow has criticized our 2006 Journal of Economic Perspectives essay describing ?Modern Macroeconomics in Practice.? Solow eloquently voices the commonly heard complaint that too much macroeconomic work today starts with a model with a single type of agent. We argue that modern macroeconomics may not end too far from where Solow prefers. He is also critical of how modern macroeconomists use data to construct models. Specifically, he seems to think that calibration is the only way that our models encounter data. To the contrary, we argue that modern macroeconomics uses a wide variety of empirical methods and that this big-tent approach has served macroeconomics well. Solow also questions our claim that modern macroeconomics is firmly grounded in economic theory. We disagree and explain why.Macroeconomics

The Heterogeneous State of Modern Macroeconomics: A Reply to Solow

Robert Solow has criticized our 2006 Journal of Economic Perspectives essay describing "Modern Macroeconomics in Practice." Solow eloquently voices the commonly heard complaint that too much macroeconomic work today starts with a model with a single type of agent. We argue that modern macroeconomics may not end too far from where Solow prefers. He is also critical of how modern macroeconomists use data to construct models. Specifically, he seems to think that calibration is the only way that our models encounter data. To the contrary, we argue that modern macroeconomics uses a wide variety of empirical methods and that this big-tent approach has served macroeconomics well. Solow also questions our claim that modern macroeconomics is firmly grounded in economic theory. We disagree and explain why.

Time inconsistency and free-riding in a monetary union

We analyze the setting of monetary and nonmonetary policies in monetary unions. We show that in these unions a time inconsistency problem in monetary policy leads to a novel type of free-rider problem in the setting of nonmonetary policies, such as labor market policy, fiscal policy, and bank regulation. The free-rider problem leads the union’s members to pursue lax nonmonetary policies that induce the monetary authority to generate high inflation. The free-rider problem can be mitigated by imposing constraints on the nonmonetary policies, like unionwide rules on labor market policy, debt constraints on members’ fiscal policy, and unionwide regulation of banks. When there is no time inconsistency problem, there is no free-rider problem, and constraints on nonmonetary policies are unnecessary and possibly harmful.Monetary policy ; Econometric models