MORGAN HEBARD 5 



elsewhere, while the transverse supra-anal plate, for a time given 

 as characteristic of that subfamily, is also worthless for any such 

 purpose. Indeed, certain species of the Oxyhaloid genus Choris- 

 oneura have a strongly transverse supra-anal plate, while others 

 have the supra-anal plate triangularly produced. Thus we are 

 forced to the conclusion that a general facies, produced by a combi- 

 nation of subtle characters, will be found the criterion for placing gen- 

 era in their proper subfamilies. In most cases this is not a difficult 

 matter to the experienced student. A Nyctiborine, Panchlorine, 

 Blaberine or other subfamily facies is readily noted. In some 

 groups, however, and usually among those showing adaptation to 

 peculiar modes of living, particularly through atrophy of tegmina, 

 wings and limb armament, such assignment may prove to be 

 extremely difficult. .\A'e have not been able to assign such genera 

 as Hyporhicnoda, Pycnosceloides, Colapterohlatta and Litopeltis 

 without long continued study and comparison with all the genera 

 which exhibited resemblance of any kind. In regard to Anaplecta, 

 we feel no hesitancy in placing the genus in the Ectobiinae, particu- 

 larly after finding that the genus Lissoblatta, though of close gen- 

 eral similarity to Anaplecta, showed a number of characters agree- 

 ing instead with Ectobiiis and its nearer allies. 



As to Chorisoueura and Plectoptera, the unarmed ventral femoral 

 margins lead us to the conclusion that it is best to assign these 

 genera to the Oxyhaloinae. Both are distinctive and widely 

 separated from any other known genera, both in different ways 

 show many indications of apparent approach to the Anaplecta. 

 and particularly to the Lissoblatta, type. Whether this is conver- 

 gence toward that section of the Ectobiinae, or indicates common 

 ancestry, we are unable to state. We do feel, however, that until 

 much more work is done in the Blattidae, these genera had best be 

 left in the Oxyhaloinae. 



The large unworked collections, frequently referred to while 

 studying the present material, show that a mere beginning has 

 been made on a modern classification of the Blattidae of tropical 

 America. The multitude of as yet undescribed genera and species, 

 when studied, will undoubtedly throw much light on many of the 

 problems which at present can hardly be solved. 



MEM. AM. ENT. SOC, 4. 



