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HARDWICKKS SCIENCE-GOSSIP. 



very plentiful some five or six years ago, since which 

 time it has not occurred in anything like full force of 

 numbers. At the time we mention we have seen as 

 many as sixty at a time feasting at one patch of 

 ■"treacles;" in fact it was quite a nuisance, 

 shouldering off every other insect which came to the 

 sweets, for it is a large, strong insect, and not to be 

 despise I as far as beauty goes; but when occurring 

 in such vast numbers as it does occasionally one is 

 apt to vote it a nuisance. At the time we speak of 

 we were compelled to kill them by hundreds ; it was 

 of no use to drive them off, they were there again 

 directly, so slaughter was our only defence against 

 them. The toads did not mind, though. We found 

 several sitting at the foot of each tree greedily gobbling 

 up such insects as fell down from under our thumb. It 

 is surprising what remarkable instinct these creatures 

 display in this matter ; they will assuredly discover 

 trees that have been "treacled," and there they sit 

 at the foot. Woe is it to any intoxicated insect 

 happening to fall to the ground ; it is snapped up in 

 an instant. We should, perhaps, explain to such of 

 our readers as do not understand " treacling," that it 

 is a method of capturing certain kinds of moths by 

 alluring them within reach by means of a sweet bait 

 composed of rum and treacle. This is brushed on 

 the trunks of trees, and is quickly scented out by the 

 insects, who congregate to sip the sweets, and thus 

 are easily captured. The toads, however, are not 

 the only purloiners of our treasures ; the bats soon 

 find out the game, and will pick off the insects from 

 the trunks of the trees as they pass to and fro in 

 flight. We have seen the cross-rail of a fence under 

 a " treacled " tree literally covered with the wings of 

 moths; the bat only devours the soft, juicy bodies, 

 clipping off the wings neatly and quickly. It is a 

 peculiar characteristic of insect life, that certain 

 species will occur at times in great profusion (as 

 above), then disappear for years altogether, or only 

 be seen in meagre numbers, again appearing, as at 

 first, in vast numbers. This peculiar trait in insect 

 life canrtot be satisfactorily accounted for ; many 

 hypotheses have been put forward, but in no instance 

 have they been substantiated by actual facts. — W. 

 Finch, jun., Nottingham. 



*x* The above from my own pen appeared in the 

 "Nottinghamshire Guardian " quite recently. 



Fox Eggars. — For the benefit of the writer of 

 the query respecting "Fox Eggars," in Science- 

 Gossip for February, I append the following 

 cutting from my article on " Lepidopterist's Work " 

 in the August issue of Science-Gossip, 1886. — 

 "Many larvae taken this month will be noticed to 

 feed slowly and in a very deliberate manner. If 

 kept, these will prove to be hybemating larva;. It 

 is often difficult so to preserve the conditions of 

 nature throughout the winter as to keep these larvae 

 in health. They frequently die, refusing all food in 

 a most obstinate manner. Of these larvae I will 

 merely mention those of the fox-moth (B. rubi), 

 which are exceedingly handsome and well worth 

 preserving. I have found them in great numbers on 

 the Lincolnshire coast, close to the sea, feeding on 

 brambles, etc. Yet, strange to say, I have never yet 

 seen the cocoon or perfect insect there. If any of 

 my readers possess a refrigerator they will be able 

 to keep these larvae throughout the winter by placing 

 them therein ; they hybernate ' full fed,' and spin 

 up almost immediately upon emergence from the 

 lethargic state. Judging from those I have kept, 

 however, I should say that they are the favourite 

 victims of the various Ichneumons." From the 

 above it will readily be seen that the larvae are 



hybemating, but I very much doubt whether they 

 will be successfully reared. — W. Finch, j'n/i., 

 Nottingham. 



"Nest of Australian Fly " and the New Zea- 

 land Spider Wasp, or Mason Fly. — The insect de- 

 scribed by Mr. George Browne (see Science-Gossip 

 for October, p. 239), is probably Pompiliisfitgax, which 

 is, I believe, found in South Australia. However 

 that may be, it is evidently closely allied to the New 

 Zealand spider wasp (also erroneously called Mason 

 Bee), and I therefore give a few particulars concerning 

 our species, which may possibly possess some interest 

 for your correspondent. The New Zealand spider 

 wasp is. I believe, a species of Fompilus {P. 

 monachus?), is black and shining with smoky- 

 hyaline wings. It may be seen in abundance in 

 many parts of the Colony. The nests which are 

 frequently found in sheds, corners of verandahs, or 

 any convenient crevice, sometimes even the living 

 rooms, behind pictures, etc., are truly wonderful 

 structures. As 1 have in my possession a number of 

 nests, and have frequently had opportunities of 

 watching the operation, I will give a short description 

 of the mode of building. I one day watched several 

 wasps on a preliminary tour of inspection, and 

 observed them busily examining a number of chinks 

 about the corners of a building ; at last an angle 

 formed by a stud and the weather-board was selected, 

 the insects, for they sometimes work in pairs, flew 

 away, but in a very few minutes returned, each 

 carrying a pellet of soft clay of considerable size. 

 This clay they at once proceeded to attach to the 

 wall, working it well with their feet, and as soon as 

 it was properly fixed they flew off for more. This 

 proceeded till a small mud shelf had been made. On 

 looking again about an hour later I found that a cell 

 measuring half-an-inch had been nearly finished, and 

 later in the day three such cells had been completed. 

 I broke open the bottom one, and found it to 

 contain a spider, not dead, but evidently paralysed 

 by a sting from the wasp. On another occasion I 

 was fortunate enough to witness the capture of 

 spiders. As each cell is completed, a spider is 

 placed in it and the egg must be immediately laid 

 either on or in its body, for the wasp at once seals up 

 the cell and proceeds to build another and so on. 

 About ten weeks after the nest was finished I broke 

 open the second cell and found a tiny whitish grub 

 feeding on the body of the spider. It is seldom that 

 more than one spider is found in a single cell, 

 probably one is usually considered sufficient for the 

 future grub, still in three instances I have found two 

 comatose spiders in one cell, but they were small, and 

 evidently the parent wasp was well able to calculate 

 the amount of food likely to be required by each of 

 her voracious children, and thus where only small 

 arachnids could be secured, she doubled the number. 

 During the whole time that building is proceeding, 

 the wasps emit a steady buzzing noise, somewhat like 

 that made by a blue-bottle, but shriller. The nests 

 sometimes contain as many as twenty cells placed 

 either in a single, double, or triple line, according to 

 the convenience of the place selected. The whole of 

 the nest including the partitions is of clay, usually 

 when dry a pale yellow colour. The outside is well 

 finished, and is corrugated and made to look some- 

 what like the sculpturing on a crayfish — each corru- 

 gation is covered with very fine striations caused by 

 the builder's feet as she works the clay and cements 

 the whole structure together. I do not wish to 

 trespass on your space, and therefore will not now 

 give a minute description of the cells, but send a 

 photograph showing a nest built on the side and 



