AMERICAN MUTILLIDiE. 219 



THE NORTH AMERICAN 91 UTILLIDJE. 



BY WILLIAM J. FOX. 



The following paper is the result of a short study of our Mutillidse, 

 with a view to a classification of the genera. It has been my 

 opinion for some time that existing classifications are unnatural, 

 inasmuch as some of the genera at present indicated, have appar- 

 ently no constant generic characteristics. In fact, one is almost 

 convinced by an examination of the family that no really serious 

 study has been made regarding it. If Sinicromyrme, Sphmrophthalma, 

 Photopsis and Pseudomethoca were held as valid genera it would be 

 necessary to form one or two genera for forms which will not fit under 

 those heads as now defined. Sphxerophthalina scceva, pennsylvanica 

 and auripilis are examples, which, in consequence of the mandibles, 

 would be referred to Photopsis, but on account of the small ocelli 

 are equally referable to Spluerophthalma. 



What have been hitherto supposed good characteristics will be 

 found to vary in studying a series. The round eyes of typical 

 Spluerophthalma merge gradually into ovate ones, and exotic species 

 are known which have the eyes partly facetted. The dentition of 

 mandibles in the female sex of that supposed genus is not constant. 

 Usually there is a small tooth present within near the apex, but in 

 many examples this will be found indistinct or absent entirely ; in 

 the latter case the mandibles present a falcate appearance. The 

 only real difference in the mandibles is to be found in those species 

 representing Photopsis (as restricted by Fox and Ash mead), in which 

 they are peculiarly and heavily built, being broadened at apex, 

 which possesses either two or three teeth. But this characteristic is 

 also found in three species otherwise referable to Sphcerophthalma 

 (in the small ocelli, etc.). These species scceva, pennsylvanica and 

 auripilis also agree with Photopsis in the unarmed first ventral seg- 

 ment and shape of marginal cell. Clearly these have as high a 

 claim to generic rank as Photopsis. They are the evidence, in my 

 mind, that proves the unity of Sph<erophthalma and Photopsis. 



As to Pseudomethoca, that has not as much claim to generic rank 

 as Photopsis. It has been defined as having two submarginal cells, 

 two discoidal cells, and with the marginal acuminate. That these 



TRA.XS. AM. KNfT. SOC. XXV. JANUARY, 1899 



