154 
A GRANITE CONTAINING LITHIA. 
July, 1880. 
said above that though Psithyrus is so like its host, in the 
oilier cases I have mentioned there is not the same obvious 
resemblance. 
Yet from an examination of various structures which one 
would expect to be the least changed by the parasitic habit, 
and from the similarity in these between host and parasite, I 
have not the least doubt that their case is the same as that of 
Psithyrus. I will here quote two passages which support 
this. Sliuckard, in his “ British Bees,” p. 49, says : “ Melecta 
resembles Anthophora, Ccelioxys has the form of Megachile, 
both in the hollow base of the abdomen and the peculiar 
manner the latter has of raising its extremity—something 
like a Staphylinus. Many other peculiarities of resemblance 
might be enunciated.” The other is from a paper by Mr. 
Edward Saunders “ On the Terminal Segments of Aculeate 
Hymenoptera ” (published in Trans. Ent. Soc., March, 1884), 
where he says : “ Still it is worthy of note that there is often 
an extraordinary general similarity in the apical segments of 
the parasites and of the bees with whom they live : Megachile, 
and Ccelioxys, Chalicodoma and Dioxys, Anthophora and Melecta, 
are striking instances of this similarity.” With regard to the 
other class I can say little. Noviada is an obvious instance. 
Whether they were originally parasites of forms allied to 
themselves, or whether from the first they attacked bees 
totally different in appearance and structure to themselves, I 
have found no means of deciding. Though now chiefly 
attacking Andrena, it is quite possible that they were not 
originally parasitic on these bees, since even now we know of 
two species which attack the Apulce or long-tongued bees, of 
the genera Eucera and Panurgus. 
Epeolus , however, which equally with Nornada, has no 
affinity with its host, appears to restrict its attacks entirely to 
Colletes. 
NOTE ON A GRANITE CONTAINING LITHIA.* 
BY MR. T. H. WALLER, B.A., B.SC. 
Some time ago I had a sample of rock sent to me by a friend 
with a request that I would determine the amount of soda and 
potash contained in it. Following the method of analysis 
which is, I believe, most generally in use, I obtained amass of 
* Read before the Birmingham Natural History and Microscopical 
Society, December 18tli, 1888. 
