30 
and Cambridgesliire fenlands, and its absence from our Norfolk 
list was therefore the more remarkable ^ indeed, it is one of 
those species to the absence of which Mr. Barrett draws attention 
in the preface to his list. I think it probable that the same 
method of work by which these were taken (a powerful lamp 
placed on the ground) may reveal the presence of other hitherto 
undetected Micro-Lep)idoptera. 
III. Macrogaster arundinis. Two cJ specimens taken by 
light at Eanworth by Mr. W. H, B. Fletcher, August 3rd 
and 5th. 
ihis insect I fear we must consider as an introduction merely. 
It is the most singular and interesting of the lej^idopterous fauna 
of the Cambridgeshire Fens ; and its naturalisation here would be 
a matter of great interest, as its other British locality is confined 
to an area of one mile square, and may be expected shortly to 
become a thing of the past. In 1873 I sent a few eggs to 
Mr. Barrett, which he turned out at Kan worth, and from that 
time to 1878 no more had been seen of them, when these two 
cf s came to light within two days of each other. The time is 
noticeable, being very late ; this species, however, spreads its 
time of emergence over several weeks, though June is its true 
season. I he fact of an odd number of years (five) intervening 
between the exposing tlie eggs and the capture of the moth 
presents some difficulties. Owing to the habit of the larva, 
which lives in the underground stem of the reed, its life 
history can hardly be worked out, but it certainly requires more 
than one year, and is generally supposed to occupy three in 
coming to maturity. Hence, should these specimens be the 
offspring of my ? of 1873, we must assume that they emerged 
irregularly toward the close of the summer of 1878, instead of 
lying over to June, 1879. 
Next to novelties, the most interesting feature of 1878 is the 
abundance of Nonagria hrevilinea. This species is as yet 
known to science only through its capture in Norfolk, and 
chiefly in one small piece of fen between Kanworth and South 
^Falsham. It seems to be one of those species whose numbers 
are specially liable to fluctuation. Although my first acquaintance 
with it was in 1871, it was not till 1876 that I was able to give 
any time to working for it, and then a groat many nights 
