in the British Museum. 3 
but the ants include both extinct and modern types, a few 
hardly separable as species from those still living. There is 
thus a rather strong probability that many of the Oligocene 
Ichneumonids do really represent extinct genera, but the 
evidence is not so complete and satisfactory as we could 
wish. We have to depend almost wholly on tie venation, 
and some of the modern genera, as geuerally understood, 
show a wide range of variation in wing-characters. ‘To take 
an extreme case, the Braconid or Alysiid genus Dacnusa 
contains species so diverse that Foerster proposed to divide 
it intol4 genera. Dacnusa or Phenolexis petiolata, Nees, is 
extraordinarily different in venation from D. or Agonia 
adducta, Hal. Jf these were found fossil, we should certainly 
place them in different genera, assuming (contrary to the 
actual facts) that wings so diverse must belong to very 
distinct sorts of insects. Thus the matter is full of uncer- 
tainties, as it stands at present, and it would be possible to 
defend the proposal of several more generic names, or the 
other extreme of noneat all. It must be said, however, that 
the fossils were compared with all the figures in Morley’s 
works on the British and Indian Ichneumonide, and with 
those in Marshall’s writings on the Braconide, and other 
publications, and with very numerous specimens in the 
Museum collections, so that in some cases the failure to find 
a satisfactory modern analogue created a strong presumption 
in favour of an extinct genus. 
HYMENOPTERA. 
Key to Gurnet Buy Ichneumonidee*. 
Aeolet PEOSONE iq oy slew als vd view aren re 
PREAOIE ECBO G Eo 3 soc ois tim» <ite. oh 2 6. 
1. Areolet distinctly pentagonal (Cryp- 
tines or Ichneumonines).......... 2. 
Areolet not pentagonal (Pimplines, 
Tryphonines, or Ophionines)f.... 3, 
* Abbreviations used in keys and descriptions :—Marginal or radial 
cell, m.; first division of radius (radial cell on first submarginal), r. 1; 
second division of radius, r.2; stigma, st.; areolet, ar.; submarginal cell, 
s.m. (only closed cells counted, so that two cells are recognised where 
some authors recognise three); basal nervure, b.u.; transverse median 
nervure, t.-m. ; transverse cubital nervure, t.-c. ; recurrentnervures, r. n. 1, 
r.u. 2; discoidal cells, disc. 1, 2, 3; combined first submarginal and 
first discoidal cells, smd.; B.M., British Museum collection ; H., R. W. 
Hooley collection; B., Brodie collection; A’C. Sm., A’Court Smith. 
t+ Orthocentrus (Tryphonine) has the areolet pentagonal, but is not 
like any of the fossils. drisa, Cameron (Ophionine), is described as 
having areolet pentagonal, but Mr. Morley has made a pencilled marginal 
note at the b.M. that it is quadrate in the type. He also notes that 
the spiracles are exactly circular. 
L* 
