NORTH AMERICAN HYMENOPTERA. 179 



Monograph of the JIUTIL,L,ID;E of North America. 



BY CHARLES A. BLAKE. 



The accumulation of much new material, in this interesting family, 

 from all parts of the country has suggested a revision of the " Sy- 

 nopsis" published in the " Transactions" in 1871. which, although 

 tolerably complete at that time, the subsequent discovery of new 

 species and also of a new genus, together with changes in nomen- 

 clature, have rendered a review of the work both necessary and de- 

 sirable. 



Full descriptions of all the species known to me are given, and of 

 those that have not been identified description's are added, in most 

 cases in the author's own words, thus assisting the student to identify 

 his material without the necessity of consulting scientific works, 

 which are often published in foreign languages, and generally diffi- 

 cult of access. 



The Mutillidae, unlike the Formicidse, or social ants, are solitary 

 in their habits, and usually found in hot sandy situations. The spe- 

 cies of the genus Mutilla are now well known to be parasitic, espe- 

 cially on various species of Bombus, and it is presumable that those 

 of the other genera of the family are likewise of the same habit. 



The characters of Sphcerophthahm, which was treated as a subgenus 

 in the " Synopsis," appear to be sufficiently constant and distinct to 

 warrant its elevation into a genus ; the smooth, round eyes separating 

 it at once from Mutilla, which have the body less coarsely sculptured 

 and not so densely hirsute. 



The selection of the name Agama used for a genus erected for the 

 reception of those species characterized by the more or less shining 

 unicolorous body, unusually large eyes and ocelli, and hyaline wings 

 was unfortunate, as it was preoccupied in the Reptilia, a fact over- 

 looked at the time. The name Photopsis is therefore substituted. 

 Of this genus the males only are known, and it is possible that the 

 females, which have thus far escaped the observations of collectors, 

 are larviform and subterraneous in their habits. 



Chyphotes is the name I propose for a new genus, characterized 

 by the binodose thorax and petiolate abdomen, the first segment of 

 which is very slender at base and suddenly dilated and nodose at 

 apex ; the eyes are smooth and round, as in Sphcerophthalma, while 

 the absence of ocelli separated it from Myrmosa 



