14 
Psyche 
[March 
In general, the abdominal structures of Notiothauma 
would indicate that this remarkable insect is a remnant of 
the ancestral Mecoptera, and is the nearest living repre- 
sentative of the ancestors of the Panorpidse. The Panor- 
podidse, however, are somewhat nearer the immediate an- 
cestors of the Panorpidse, occupying a position intermedi- 
ate between the Notiothaumidse and Panorpidas, and they 
are also related to the Choristidae. The Choristidae occupy 
a position at the base of the lines of descent leading to the 
Bittacidae. Certain features suggest a relationship between 
the Boreidae and Nannochoristidae, but these insects are 
too highly modified to determine their closest relatives 
among the other Mecopterous families, although the Panor- 
pidae may represent the types from which the Boreidae were 
descended, judging from characters other than the male 
genitalia, and the Nannochoristidae exhibit some affinities 
with the Panorpodidae. 
ABBREVIATIONS 
a Apical portion of genital style (stylapex). 
ap Anal papilla (anopapilla). 
b Basal tubercle of genital style (basotuberculus). 
be Paired tergal processes (bicornua). 
bs Basal portion of phallus (basiphallus). 
c Dorsal and ventral stylocondyles, or pivotal processes of geni- 
tal styles. 
cc Coxal hollow (coxocrater). 
ce Cerci. 
cx Genital coxites (gonocoxites or gonocoxae). 
d Dorsal phallic valves. 
e Epiandrial processes or lobes (surgonopods, surstyli, epipro- 
cessi, etc.) 
en Endostyle. 
ep Epiandrium or ninth tergite. 
es Epistyle, or process of genital style to which the extensor 
muscles are attached. 
g Dorsal epiandrial process. 
