36 
A short notice, published by the same author two years 
later in the Entom. M. Mag. London, 1892, p. 110, may likewise 
be reproduced here: 
ythis fine mimicking Dipteron is not quite so numerous 
in this district this season as it was at this time last year. 
I think it may in some measure be due to the greater rainfall 
of last winter, in flushing the stagnant and swampy pools 
where the larvae chiefly exist. I was lately at a woolscouring 
works half a mile from Ashburton, and observed the larvae in 
hundreds swimming about in the fat-barrels. Some of the latter 
had remained where they stood for years, and were filled with 
a thick, black, strong-smelling liquid; the larvae however ap- 
peared to thrive well in the atrocious stutf.* W. W. Smith, 
Ashburton, New Zealand, Jan. 5, 1892. 
It is singular, and suggestive of reflection, that two conti- 
nents, nearly antipodal, should have been invaded by HE. tenaxr 
almost simultaneously, that is, within an interval of less than 
twenty years. This simultaneousness becomes still more signi- 
ficant when we contemplate it in contrast with the totally 
different circumstances under which the invasion took place on 
either side. In North America, during four centuries of con- 
stant intercourse with Europe, not a single specimen of L. te- 
nax seems to have been imported to the eastern coast of the 
United States. The invasion came overland from the West, 
a region from which it hardly could be expected. To New 
Zealand, on the contrary, /. tenaz has been imported after a 
comparatively short period of colonization and, in all proba- 
bility, ,direct by mail steamers which have plied monthly 
between S. Francisco and Auckland for the last twenty years“ 
(see above p. 35). The distance from Liverpool to New York 
is about 3200 miles; that from S. Francisco to Auckland must 
be more than twice as long. (1) This great disparity of re- 
(1) I have no data at hand, but judge by the length of the average pas- 
sage of steamers. ‘he distance from 8. Francisco to Brisbane is, as far as | 
know, 7000 miles. 
