PREFACKH. 
Tue object of the present Catalogue is to give a complete List of 
all the genera and species of Hemiptera Heteroptera known to 
exist in the collections of European and American Entomologists. 
The letters a, b, c, &c., after the species, denote the specimens now 
contained in the British Museum, followed by the habitat and the 
mode in which each of them was obtained; and the absence of 
these letters indicates the species which are desiderata, and there- 
fore desirable to be procured for the collection. 
J. EK. GRAY. 
British Museum, 
August Ist, 1873. 
