October, 1906. J 217 



nimierous littlo tubes (such as Mr. Saunders liad described) projecting 

 from the sandstone, and evidently formed of substance extracted from 

 it. Some, apparently complete, measured about 20 mtn. long by 4 mm. 

 broad. These started from the surface horizontally (at right angles 

 to it), and gradually curved over downwards till they became perpen- 

 dicular. Others were in various stages of construction — some nearly 

 complete, some only just beginning to appear, and on some of them 

 I saw the wasps actually at work, bringing out sandy particles from 

 the holes, kneading them up with their mouths, and apparently 

 glueing them with saliva to the extremity of the unfinished tubes. T 

 was disappointed to find only ? ? , and concluded that the (^ ^ were 

 over, but of this I am now doubtful — however, I could not find them. 

 I w'as also disappointed that I could see no Ch ry si ds \i^\img the 

 burrows, but neither then, nor on any later occasion while I had the 

 colony under observation, did any such visits occur. A few specimens 

 of C. igmta, and a good many of Q. cyanea, lighted on the walls from 

 time to time, but never entered nor seemed to notice the tubes ; and 

 as the latter species is known to infest Trypoxylon, and T.Jlgulus, L. 

 was quite as abundant as the wasp, inhabiting simple {i. e., tubeless) 

 burrows in the same walls, I was soon convinced that the holes of 

 this insect and not those of the Odynerus were the attraction that had 

 brought cyanea thither. Ignifa infests many species of industrious 

 Hymenopfera, and may have been attached to Osmia solskyi, Mor. 

 (== fulviventris, E. S.), which also occurred in the walls, together (as 

 I was pleased to see) with its " cuckoo " Stelis phceoptera, Kirb., 

 which I had not before taken in this district. 



Though no Clirysid or other recognised parasite was seen to enter 

 or emerge from any of the reniformis burrows, I was surprised to see 

 that the Trypoxylons did so repeatedly. These visits were much too 

 frequent and protracted to have been merely accidental ; and as Try- 

 poxyJon is certainly no parasite, but a diligent hunter after spiders, I 

 can only conjecture that it may have expected to find spiders lurking 

 in the holes, as they certainly did (for I saw plenty of their webs 

 there) in other holes all over the walls, which holes had quite the ap- 

 pearance of having once been occupied by burrowing Hymenoptera. 



This year I resolved to visit the colony earlier, and if possible 

 secure specimens of the ^ ^ , w^hich I had not yet taken in England. 

 I went over accordingly in June, but met with unexpected difficulties. 

 My last year's friend had left Chobham, and I found the whole en- 

 closure elaborately protected from trespass, and in fact made quite 

 impenetrable on all sides, with padlocks and barbed wire. At last, 



T 



