12 
Psyche 
[March 
higher insects. The penis valves have been homologized 
with the endopodites of the genital limbs of the ninth seg- 
ment, while the gonostyli have been homologized with the 
exopodites of the genital limbs (gonopods) whose protopo- 
dites are represented by the gonocoxites, but the homologies 
of the genital valves of the male insect have not been defi- 
nitely determined, and it is preferable to refer to them as 
parts of the phallosome, as is done by the Dipterists. The 
ornate valves labelled d in fig. 15 of Notiothauma, lie 
on each side of the gonopore and apparently represent the 
dorsal valves d of the Panorpid shown in fig. 8, while the 
ventral valves v of fig. 15 of Notiothauma may represent 
the ventral valves v of the Panorpid shown in fig. 8, al- 
though the ventral valves v of Notiothauma are poorly 
developed, and were difficult to make out in the dried speci- 
men available to me for study. 
In such Panorpids as Panorpa lugubris, shown in fig. 25, 
the dorsal valve d of each side is not divided, but the ven- 
tral valve of each side is divided into an upper ventral valve 
labelled u and a lower ventral valve labelled l in fig. 25. 
The ventral valves of Notiothauma are not thus divided 
into an upper and lower branch, but in Chorista (fig. 12) 
one of the branches of the lower valves forms one of the 
penisfilum valves labelled pv in fig. 12, and this pair of 
valves becomes greatly elongated to form the so-called 
penisfilum pf of the Bittacidae (fig. 11), so that in this, 
and certain other respects, Chorista is more like the ances- 
tor of the Bittacidse, while Notiothamma is more like the 
ancestor of the Panorpodidse and Panorpidse. The phallo- 
some ps of Nannochorista shown in fig. 10 is much reduced 
and in Boreus (fig. 9) the parts are usually retracted, al- 
though in the specimens shown in figs. 31 and 34 of plate 
10, in Vol. 48 of the Transactions of the Amer. Ent. Soc. 
for 1923, a large eversible membranous penis was visible, 
being apparently extruded at the time of mating. The parts 
are as much alike in the Boreidse and Nannochoristidse as 
any, but the resemblance is not very marked in these two 
families, and it is difficult to determine where they branched 
off in the phylogenetic tree of the Mecopteran families. 
