232 SCIENCE PROGRESS 



new genus and species of Cecidomyidse, Mycocecis ovalis, from 

 North Sussex. The early stages of this gall-fly are passed 

 among bark-encrusting fungi, upon which they form blister- 

 like sweHings. It appears to be the first record of a Cecidomyid 

 fly producing a fungus gall. The dispersion of flies by flight 

 forms the subject of a paper by Bishopp and Laake (Journ. 

 Agric. Res., 31, No. lo). An extensive series of experiments 

 was carried out with several common species of Diptera, and 

 an estimated total of 234,000 specimens was used. These 

 were marked by being liberated into bags containing finely 

 powdered red chalk or paint pigment and afterwards allowed 

 to escape. In order to ascertain the distance of dissemination, 

 baited traps were set at measured distances in different direc- 

 tions from the point of liberation. The experiments carried 

 out show that under rural and urban conditions flies have 

 marked powers of diffusion, which applies to both the sexes, 

 although in very different proportions in different species. 

 Thus the common house-fly, Musca domestica, was recaptured 

 at a distance of over thirteen miles from the point of libera- 

 tion, Chrysomya macellaria fifteen miles, and Phormia regina 

 nearly eleven miles. The fact that many favourable feeding 

 and breeding grounds were passed by the flies appears to 

 indicate that, in so far as the above three species are concerned, 

 very evident migratory habits are noticeable. The authors 

 conclude that, under natural conditions, the influence of 

 moderate winds on dissemination is not of great importance. 

 K. M. Smith and J. C. M. Gardner have published a well-illus- 

 trated series of observations on the metamorphosis and control 

 of three insects affecting vegetables — viz., the onion, carrot, 

 and celerj'- flies. The work forms vol. i of Insect Pests of the 

 Horticiilturalist (London, Benn Bros., 1922). 



PALSIONTOLOGY. By W. P. Pycraft, F.Z.S.. A.L.S., F.R.A.S.. British 



Museum (Natural History), London. 



Though the records of much valuable work have been pub- 

 lished during the last six months, most of these are in the 

 nature of details such as are filed for future reference. But 

 among these are one or two memoirs of a more comprehensive 

 character, and they call for special comment. 



We are indebted to Dr. Gertrude L. Elles for an extremely 

 interesting, and valuable, history of " The Graptolite Faunas of 

 the British Islands " (Proc. Geol. Assoc., vol. xxxiii, 1922). 



While the Graptolites are generally regarded as allies of the 

 Hydrozoa, Dr. Elles holds that it is by no means certain that 

 they belong even to the Coelenterata, and that they should 

 therefore be regarded as forming a distinct class, the Grapto- 



