1967] 
Wilson, Carpenter , Brown — Mesozoic Ants 
3 
the evolution of venational and body traits proceeded concordantly 
before, during or after the transition from parasitic to aculeate 
Hymenoptera. In other words, we do not know from the present 
evidence whether the diagnostic body characters of the whole insect 
Cretavus would place it in the Aculeata or not. 
The reason for the apparent absence of social insects before the 
Tertiary may be due at least in part to the general scarcity of Creta- 
ceous insects. The most notable relevant Cretaceous deposit, the 
Cedar Lake amber from Manitoba studied by Carpenter and his 
associates (1934), contains moderate numbers of insects, and some 
are Hymenoptera, but these include no ants or aculeates of any 
kind. Two explanations seem possible: either the Cedar Lake amber, 
which has not been precisely dated within the Cretaceous, 3 originates 
from an early part of the period, prior to the origin of the aculeates, 
or else the early aculeates were too large to be enclosed in the small 
amber pieces that characterize the deposit. Amber has been found 
in Cretaceous deposits along the Arctic coastal plain of Alaska 
(Langenheim, Smiley and Gray, i960) but very few insects are 
included and no aculeates have been reported. 
For many years numerous pieces of amber have been recovered 
from sediments exposed along the coastal plain of Maryland and New 
Jersey, as well as on Staten Island and Nantucket. These pieces 
have apparently been derived from at least two formations, the 
Raritan and the Magothy, both of which are referable to the lower 
part of the Upper Cretaceous. The first published account of this 
amber appeared nearly 150 years ago (Troost, 1821) but, in spite 
of frequent observations on the occurrence of the amber, almost no 
records of insect inclusions have been published. Indeed, the only 
account of an inclusion was that in Troost’s original report on the 
amber (1821), which contained a “description of a variety of amber 
and of a fossil substance supposed to be the nest of an insect”. 4 
3 Langenheim, Smiley and Gray (1960, p. 135) refer to the Cedar Lake 
amber as of “presumed Late Cretaceous Age”. However, Dr. Langenheim 
informed me subsequently (pers. com., 1964) that he had no knowledge of 
evidence dating the amber at any specific level within the Cretaceous. 
[F. M. C.] 
4 lt is of interest to note that at the first meeting of the Cambridge Entomo- 
logical Club, January 4, 1874, Professor Hermann Hagen presented an 
account of this specimen, concluding that it was a group of galls on a 
twig (Hagen, 1874). No formal description was ever published. 
Explanation of Plate 2 
Sphecomvrma freyi , worker no. 2, paratype. The head is viewed obliquely 
from below r and in front. 
