40 BULLETIN 143, UNITED STATES NATIONAL MUSEUM 



D. fvXvohirta found in the cells of the same bee by Mr. Charles H. 

 Hicks. The latter also found the remains of D. asopus (Cresson) in 

 the cells of Dianthidiwm species. D. vesta (Cresson) is said by 

 Rucker (1903) to have been reared from Chalyhion caeruleuni 

 (Linnaeus), but there is some doubt as to whether the Mutillid was 

 correctly identified. More recent rearings from this host have always 

 produced Sphaerophthahiia species as the parasite. The writer has 

 not been able to obtain the specimens reared by Rucker in order to 

 verify the determination so that the relationship can not be regarded 

 as definitely established. D. foxi (Cockerell) is reported by Cock- 

 erell (see remarks on this species) to be parasitic in the nests of 

 Diadasia species. 



SPECIF/C CHAKACTBRS 



The species of Dasyniutilla do not lack characters by which they 

 may be distinguished from one another, although many of them 

 appear superficially to be almost indistinguishable. Many of the 

 characters are superspecific ; that is, the same character is present in 

 two or more species. It is therefore possible to arrange the species 

 in groups, the units of each group bearing a close relationship to 

 one another. The superspecific characters are as follows: Presence 

 or absence of a median pit densely filled with erect hairs on the 

 second abdominal sternite of the males, presence or absence of a 

 median longitudinal row of erect hairs, simulating a carina, on the 

 second abdominal sternite of the males; presence or absence of an 

 apical fringe of hairs on the last tergite of the males; structure of 

 the male genitalia ; presence or absence of a prominent tooth on the 

 posterior trochanters of the males ; size of the ocelli and the eyes in 

 the males ; structure of the posterior tibiae in the males ; structure of 

 the apex of the intermediate and posterior femora in both the males 

 and the females ; size of the eyes in the female ; presence or absence 

 of tubercles at the posterolateral angles of the head in the females ; 

 shape of the thorax in the females ; and the presence or absence of a 

 scutellar scale in the females. Specific characters are as follows: 

 Relative lengths of the first and second segments of the flagellum; 

 relative widths of the head and thorax; sculpture of the various 

 sclerites of the body; color of the integument and the pubescence, 

 including maculations of the body due to both; presence or absence 

 of a carina bounding the antennal scrobes above ; presence or absence 

 of a median emargination of the pronotum of the males ; shape and 

 sculpture of the tegulae of the males; color of the calcaria of the 

 males; sculpture of the genae of the females and sculpture of the 

 pygidium of the females. 



The genitalia of the males have proved of inestimable value in 

 settling certain points, especially in groups of males that are super- 



