1960] 
MacLeod — Boriomyia 
37 
Circumstances have thus conspired to make it seem that Kirnminsia 
is a taxonomic segregate from the closely allied genus Boriomyia and 
that the question of whether to recognize one genus or two simply 
depends on the emphasis which one places on the differences in the 
venation of these two groups. Actually this is misleading, for as long 
ago as 1940 Carpenter pointed out that the differences between these 
two genera are much more far-reaching than had been suspected, in- 
volving not only consistent differences in venation, but fundamental 
differences in the basic organization of the genitalia of both sexes. 
Indeed, it was Carpenter’s contention that the true affinities of Bori- 
omyia lie not with Kirnminsia at all, but rather with the genus Me- 
galomus. 
The findings of the present study lend complete support to this 
view. Details of the biology of the Palaearctic Megalomus hirtus 
(Linne) including several excellent figures of the larvae have been 
published by Killington (1934, 1937a), while the present author has 
reared the immature stages of an unidentified species of Megalomus 
from Mexico. In addition, modern figures and descriptions of larvae 
of species of Kirnminsia, W esmaelius, Psectra, Sympherobius, Hetne- 
robius, Micromus, and Drcpanepteryx have also been provided by 
Smith (1923, 1934), Killington (1936, 1937a, 1946) and Fulmek 
(1941) and as the writer has been able to rear or study larvae of 
species of the last four of these genera, detailed comparisons of a 
variety of larval types of the Hemerobiidae have been possible. 
Only in very general features shared by the larvae of all known 
hemerobiids do those larvae of Micromus, Hemerobius , W esmaelius 
and Kirnminsia which are known bear any close structural resemblance 
to the larvae of the remaining groups and they will not be discussed 
further. A series of striking similarities is to be found in the larvae of 
Boriomyia and Megalomus involving the shape of the labial palpi, 
the form of the terminal segment of the antenna and in the appearance 
of the mature larva. The swollen, inflated shape of the labial palpi, 
particularly striking in the first instar larvae, but noticeable in the 
later two instars as well, is present only in Sympherobius and Psectra 
in addition to Megalomus and Boriomyia although it has never been 
observed to reach the extreme degree in the first two of these genera 
that it does in the latter two. The extremely shortened terminal seg- 
ment of the antenna, surmounted by an apical seta nearly as long as 
or longer than this segment, is known to the writer only in Boriomyia 
and Megalomus. A much less drastic reduction in the terminal seg- 
ment occurs in Sympherobius, but here the segment is somewhat flask- 
