262 



[November, 



are laid, ns lie says, from only one surface of the leaf (the upper one?). The 

 Iris (pseud acorus) leaf consists more of air than of leaf tissue, the air being in 

 cells in longitudinal rows, each cell about 5 mm. long, though some reach 12 or 

 more, and about one millimetre wide. The eggs are laid in these cells, never 

 more than one in each cell, though they may be very close together. After 

 watching the eggs being laid, it is after a few seconds practically impossible to 

 identify the spot, but by splitting the leaf longitudinally the eggs are quite 

 conspicuous in their several cells — on a small bit of leaf I still have I find 19 

 exit holes of the youug larvae ; this much exceeds Dr. Scott's count, but his 

 specimens were laid naturally, mine in confinement in a jar. Notwithstanding 

 this pressure, there is (and was) no example of two eggs in one cell. The 

 nearest /. pseudaccrus grows a mile and a half from hei'e, aud I fed the larvae, 

 who took to it fairly well, on the leaves of a dwarf yellow-flowered Iris in the 

 garden. I also gave some leaves of this to the flies for oviposition, with a 

 comically tragic result. This Iris has a thin leaf and contains no air-cells, and 

 compared with /. pseudacorus it may be called solid. The result was that 

 a. micans (under compulsion of captivity perhaps) essayed to oviposit in it> 

 with the result that the ovipositor perforated the leaf, and the egg was laid in 

 the open on the other side. This sawfly does not make a pocket for her q^^, 

 but takes advantage of a natural pocket in the food-plant, which is, however, 

 palatially too large to fit the egg as a pocket mads by the fly usually does. — 

 T. A. Chapman, Betiila, Reigate : October 1921. 



Insect Fexts in Leeds and Hors forth. — We copy the following from the 

 "Yorkshire Post'' of September 30th: — "Insect pests have caused much 

 annoyance in Leeds and Horsforth recentl3\ A medical practitioner at Horsforth 

 stated yesterday that during the last few weeks he had treated half-a-dozen 

 persons who were bitten by mosquitoes in that portion of Horsforth which ad- 

 joins Newlay. Happily none of the cases proved serious. This doctor was 

 bitten himself the other day, and he is confident that the bites were identical 

 with those with which he was familiar on active service in France and 

 Flanders. A few complaints of mosquito bites have been heard in Leeds, but 

 apparently the nuisance is not so widespread as to be the subject of an ofiicial 

 report to the public health authorities. Dr. J. J. Jervis, the Medical Officer of 

 Health for Leeds, informed one of our representatives last night that the most 

 serious inconvenience in the city at the present time arises from the unwelcome 

 presence of crickets, which swarm from refuse tips in certain parts of Leeds, 

 and make life almost unbearable for the occupants of adjacent houses. The 

 insects are discovered in most unlikely places, and their constant chirping pre- 

 vents people from sleeping. Strong complaints about this nuisance have been 

 received by the public health authorities." — Eds. 



^oriiitus. 



The South London Entomological and Natural History Society: 

 August 25th, 1921.— Mr. K. G. Blair, B.Sc, F.E.S., President, in the Chair. 



Mr, Edwards exhibited the black " cherrj^-aphis,'' Myzus cerasi, and the 

 greenhouse " white-fly," and referred to the methods of control of the latter 



