74 Mr. W. E. Shuckard’s Descriptions 
glimpse tells us that it is more closely allied to Tachytes, Pz. ( Lyrops , 
111.) than to any other fossorial insect, view being had to general habit 
rather than to any single character ; nor does it agree with Alyson in 
more than a single character. Reniform eyes, which Alyson has not, 
and which is one of the chief characters of the present genus, we find 
straggling through several families of the Aculeate Hymenoptera. 
Amongst the Mutillidce we discover it in many males of Mutilla, and 
slightly so in Myzine, but always in Scolia, Sapyga, Polochrum, and 
Trypoxylon, and slightly in Philanthus, when we at last observe it 
as almost universal in the Vespadce , wherein the instances in which 
it is not so form rare and remarkable exceptions, and one of which 
the present paper will describe. The only character in which Pison 
agrees with Alyson is the petiolated second submarginal cell, which 
we also find in the just-described genus Exeirus, amongst the Pom- 
pilidee, and in Miscophus, Nysson and Cerceris. His subsequent 
observations on the families are of but little value, as they point out 
no new affinities ; and the only generic character he has really 
added is the single calcar of the intermediate legs, to which I may 
supply, as generic also, the longitudinal furrow of the metathorax 
with its central carina. I consider myself right in treating this as 
generic, as it occurs in all the species, but in the Pison Spinolce it 
is rather less developed. That the metathorax frequently yields 
generic characters in these insects, we find in the niucro of Oxy- 
belus, the spines of Nysson and Alyson, the triangle of Gorytes, 
and the carinae and obtuse spines of Ampulex. I may, therefore, 
be justified in treating it as such. The segments of the abdomen 
are not constricted as in Cerceris, but the margin of the first three 
are much depressed, which gives them slightly this appearance, 
aided, too, by the sometimes considerable gibbosity of the first seg- 
ment. There is great specific diversity in the form and size of the 
second submarginal petiolated cell, as well as in the mode of its re- 
ceiving the recurrent nervures, which are sometimes interstitial, 
inosculating with the transverse cubital nervures, and sometimes 
received within it; and in other instances which, in accordance with 
my adopted principles, I must consider as subgeneric, — the first 
submarginal cell receives the first recurrent nervure towards its 
extremity, and the second receives the second recurrent about its 
centre. I am enabled here to add seven new species to those al- 
ready described. The genus appears to be widely distributed, as 
there is one European and four African, including that from St. He- 
lena, one from the Mauritius, and three from the Australian group, 
where it appears to take the place of Tachytes, Pz. ( Lyrops , 111.) 
