39 



of the house-fly in winter. Does it hibernate ? Dr. Gahan thinks 

 the larvas feed on snails in the winter ; but this cannot be true of 

 all districts, as there are some where flies are plentiful, but there 

 are no snails, so that this theory is limited to certain localities. I 

 should rather suppose that the larvse spend the winter in the refuse 

 heaps which are found in most gardens. 



The very rapid spread of the Gipsy-moth in the United States 

 has somewhat puzzled the naturalists of that country, but probably 

 some light has been cast on it by the experiments of two Austrian 

 investigators, Messrs. Wachtl and Kornauth, who have described 

 some peculiar hairs found on the larvre of Psilura moiiacha in their 

 first stage. Similar hairs, they state, are present on the first stage 

 larvfe of Li/mantria [Portltetria) liispar. Such hairs are furnished 

 with globular enlargements near their base, supposed to be dis- 

 tended by air or gas. These hairs are distinguished as " prostatic 

 hairs," and the globules as " ferophores." Experiments conducted in 

 the Austrian forests showed that P. )iioiiacha larvae were carried 

 long distances by the wind, and by analogy it was assumed that L. 

 (lispar larvfe, being similarly endowed, would also take aerial voyages. 

 Microscopical examination of a first-stage larva revealed two kinds 

 of hairs arising from each of the tubercles which are found along 

 the body. A few of these hairs are slender, and nearly half the 

 length of the larva, whilst a considerable number of shorter hairs 

 are furnished with globular swellings near their base. Whether 

 these aerophores assist the young larvfe in their distribution by 

 making them more buoyant is not actually known, but experiments 

 in America show that the larvfe can be carried by the wind for a 

 third of a mile, from a point less than six feet above the ground, 

 and that the most favourable time for the dispersion is when the 

 temperature is above 65°, and the wind velocity is over fifteen miles 

 an hour. These experiments appear to offer an explanation of the 

 otherwise unaccountable spread of L. ilispar to new territory. The 

 larvje have been known to be carried in this manner to a maximum 

 distance of twenty-six miles. 



In connection with the above, it may be recalled that in 1906 

 the Tachinid fly Compsilura concinnata was imported into the United 

 States with a view to controlling the ravages of L. dhpar and 

 Nyijinia ph(Borrhea, those of the brown-tail moth ; the introduction 

 was attended by great success. 



It was reported in the press, a short time since, that a Dutch 

 queen bee, considered to be immune from the attacks of the " Isle 



