Some Notes on Heteropteran Trichobothria

Excerpt: There has been much recent interest in the comparative morphology of the Heteroptera. This work has emphasized the land bugs, or Geocorisae, and has been concerned with working out the relationships and taxonomic placement of the higher categories (categories above the genus), and with the phylogenetic lines and sequences of these higher categories. The geocorisine groups with which I have been most concerned are in the closely related superfamilies Lygaeoidea, Pyrrho- coroidea, and Coreoidea (see Schaefer, 1964, for a discussion of the relationships among these groups). Another superfamily, the Pentatomoidea, is less closely related. All four of these superfamilies have arolia and pseudarolia, and all four have trichobothria. Because they possess this last character in common, the four are grouped together under the name Heteroptera Trichophora (Tullgren, 1918), aname of no nomenclatorial standing but nevertheless convenient. Trichobothria are long hairs arising from often darkened sockets on the relatively bald abdominal venter. They are usually easy to distinguish from other hairs, because they are longer, have a darkened base, and are arranged symmetrically in a distinctive pattern on each segment. These patterns and the number of trichobothria in them are characteristic of the higher categories of the Trichophora. Since the trichophoran families are closely related, and since this close relation- ship has been established on evidence from other morphological features than trichobothria, one might look for phylogenetic significance in the variety of patterns. However, very little is known about the function and phylogenetic origin of trichobothria. I shall speculate here on their function and their phylogenetic significance, but more must be learned about trichobothria before speculation becomes knowledge

Annotated Checklist of the Pentatomidae (Heteroptera) of Connecticut

We provide town data for the Pentatomidae in Connecticut. Although this state has been much collected, most sampling has been limited to only a few lo- cations. Species newly recorded for Connecticut are: Halyomorpha halys (Stål), Hymenarcys nervosa (Say), Banasa euchlora Stål, B. sordida (Uhler), and Perillus bioculatus (Fabricius). Podisus neglectus (Westwood) may occur in the state. Other species found in neighboring states may eventually be found in Connecticut: Picromerus bidens (Linnaeus), Rhacognathus americanus Stål, Mcphersonarcys aequalis (Say), Thyanta custator custator (Fabricius), T. custator acerra McAtee, and Amaurochrous brevitylus (Barber and Sailer). We briefly analyze these data, recognizing some faunal elements. More collecting needs to be conducted in the state, so that distribution patterns outlined here can be more broadly understood, and so that species of potential conservation concern can be identified

Unemployment and econometric learning

We apply well-known results of the econometric learning literature to the Mortensen-Pissarides real business cycle model. Agents can always learn the unique rational expectations equilibrium (REE), for all possible well-defined sets of parameter values, by using the minimum-state-variable solution to the model and decreasing gain learning. From this perspective the assumption of rational expectations in the model could be seen as reasonable. But using a parametrisation with UK data, simulations show that the speed of convergence to the REE is slow. This type of learning dampens the cyclical response of unemployment to small structural shocks

Annotated Checklist of the Pentatomidae (Heteroptera) of Connecticut

We provide town data for the Pentatomidae in Connecticut. Although this state has been much collected, most sampling has been limited to only a few lo- cations. Species newly recorded for Connecticut are: Halyomorpha halys (Stål), Hymenarcys nervosa (Say), Banasa euchlora Stål, B. sordida (Uhler), and Perillus bioculatus (Fabricius). Podisus neglectus (Westwood) may occur in the state. Other species found in neighboring states may eventually be found in Connecticut: Picromerus bidens (Linnaeus), Rhacognathus americanus Stål, Mcphersonarcys aequalis (Say), Thyanta custator custator (Fabricius), T. custator acerra McAtee, and Amaurochrous brevitylus (Barber and Sailer). We briefly analyze these data, recognizing some faunal elements. More collecting needs to be conducted in the state, so that distribution patterns outlined here can be more broadly understood, and so that species of potential conservation concern can be identified

Recent changes in British wage inequality:Evidence from firms and occupations

Using a dataset covering a large sample of employees and their mostly very large employers, we study the dynamics of British wage inequality over the past two decades. Contrary to other studies, we find little evidence that recent increases in inequality have been driven by differences in the average wages paid by firms. Instead greater dispersion within firms can account for the majority of changes to the wage distribution. After controlling for the changing occupational content of employee wages, the role of average firm residual differences is approximately zero; the modestly increasing trend in between-firm wage inequality is explained by a combination of changes in between-occupation inequality and the occupational specialisation of firms. It is possible that previous studies, which assign some of the importance of changes in the between-firm component to industry, have misrepresented a significant role for occupations. These results are robust across measures of hourly, weekly and annual wages

Recent changes in British wage inequality: evidence from large firms and occupations

Using a linked employer-employee dataset covering large firms, we present new evidence on British wage inequality trends over the past two decades. Differences between firms in the average wages they paid did not drive these trends. Between 1996 and 2005, greater wage variance within firms accounted for eighty-six percent of the total increase in wage variance among employees. In the following decade, wage inequality between firms continued to increase, whereas overall wage dispersion decreased. Approximately all the contribution to inequality dynamics from estimated firm-specific factors, throughout the employee wage distribution, disappears after accounting for the changing occupational content of wages

Cyclical labor costs within jobs

Using UK employer-employee panel data, we present novel facts on how wages and working hours respond to the business cycle within jobs. Firms reacted to the Great Recession with substantial real wage cuts and by recruiting more part-time workers. A one percentage point increase in the unemployment rate led to an average decline in real hourly wages of 2.6 percent for new hires as well as for job stayers. Hiring hours worked were substantially procyclical, while job-stayer hours were acyclical. These results show that real wages are not rigid and that the labor costs of new hires are especially flexible

Unemployment and econometric learning

We apply well-known results of the econometric learning literature to the Mortensen-Pissarides real business cycle model. The unique rational expectations equilibrium (REE) is always expectationally stable with decreasing gain learning, and this result is robust to over-parametrisation of the econometric model relative to the minimum state variable form used by agents (Strong E-stability). And so, from this perspective, the assumption of rational expectations in the model is not unreasonable. However, using a parametrisation with UK data, simulations suggest that the implied rate of convergence to the REE with least squares learning is however slow. The cyclical response of unemployment to structural shocks is muted under learning, and a parametrisation which guarantees root-t convergence is generally not consistent with attempts to match the observed volatility of labour market data using the standard model

Why wages don't fall in jobs with incomplete contracts

We investigate how the incompleteness of an employment contract -discretionary and non-contractible effort - can affect an employer's decision about cutting nominal wages. Using matched employer-employee payroll data from Great Britain, linked to a survey of managers, we find support for the main predictions of a stylised theoretical framework of wage determination: nominal cuts are at most half as likely when managers believe their employees have significant discretion over how they do their work, though the involvement of employees, via information sharing, reduces this correlation. We also describe how contract incompleteness and wage cuts vary across different jobs. These findings provide the first observational quantitative evidence that managerial beliefs about contractual incompleteness can account for their hesitancy over nominal wage cuts. This has long been conjectured by economists based on anecdotes, qualitative surveys, and laboratory and field experiments.Output Status: Forthcomin