69 
of New Exotic Aculeate Iiymenoptera. 
Obs. — This genus, which lias precisely the habit of a male Mel- 
lows, is remarkable as being the only one yet characterized among 
the Mutillidce, in which the second submarginal cell receives both 
the recurrent nervures, as also in its clypeus, which approaches to 
the structure of that of Cerceris. I have named it in allusion to 
its presumed habits of frequenting sandy situations ; it may subse- 
quently prove to be the male of Mr. Westwood’s genus Diamma,* 
in which case it must necessarily fall ; but as there is so great a 
discrepancy between them, I judge only from analogy, and have, 
therefore, thought it desirable to characterise it until future obser- 
vations shall corroborate, or remove, my suspicion. 
A similar kind of circumstantial evidence induces me to consider 
that the genus Thynnits j~ will eventually prove to be the males of 
the genus Myrmecodes ; but I have no doubt that the first box of 
insects sent by Mr. Lewis, or his next letter, will determine if I am 
correct. Acting upon this view, I have removed 'l'hynnus from the 
Scoliadce, where it was placed by Latreille, amongst which he would 
have also located the present genus. Insects with apterous females 
(as I presume this to be) are difficult to determine until positive 
observations are made by duly qualified collectors. 
Species 1 . Psamatha chaeybea, Shuck. Plate VIII. fig. 1 . 
Chalybea , nitida, griseo-pubescens ; margine postero prothoracis albulo ; 
abdomine utrinque maculis quatuor albidis; pedibus rufis et tar sis 
piceis. $ . 
Length 6 lines. Expansion of the wings 11^ lines. 
Chalybeous, shining, loosely covered with grey hair ; the antennae 
black ; the lower half of the internal orbit of the eyes, a short line 
on their exterior at the vertex, the lateral productions of the cly- 
peus, and the internal margin of the mandibles at the base, all white ; 
the cheeks covered with long hair, as well as the thorax, which is 
slightly punctured ; the prothorax with a narrow white line at its 
posterior margin, interrupted very slightly in the centre ; the wings 
subhyaline, their nervures black; the legs red, with the coxae and 
* Proceedings of Zoological Society, April 14, 1835. 
t This, I have since discovered, has been stated by Klug, in a paper on the Eyes 
of Insects, in the Transactions 1 of the Academy of Beilin, and, I presume, from 
the observation of a correspondent in New Holland. My own supposition pro- 
ceeded from analogy. Mr. Lewis has since confirmed this by having detected the 
Thynnus variabilis, Leach, in copula with an apterous female congeneric with the 
Tiphia ( Myrmecodes , Latr.) pedestris, Fab. 
1 Abhand. der Akademie der Wissenschaften, fur 1831, p. 307. 
