THE ENTOMOLOGIST. 
Vou. XIX.] NOVEMBER, 1886. [No. 282. 
ARE CEROSTOMA RADIATELLA AND C. COSTELLA 
DISTINCT? 
By Ricuarp Soutu, F.E.S. 
Mr. T. J. Henperson, of Glasgow, when sending some insects 
from Scotland lately, included a series of Cerostoma radiatella 
and C. costella, concerning which he writes :—‘‘I have a strong 
impression these are but one species; they appear always to 
occur together, and intermediate varieties are common enough.” 
Looking at the specimens sent, I am quite inclined to agree with 
Mr. Henderson, and should be exceedingly puzzled to say whether 
some of the examples are referable to radiatella or costella. 
My series of each of these insects, from various localities in 
the South of England, would at first sight appear to consist of 
two clearly distinct species. Both are more or less variable as 
regards colour of fore wing; but the broad patch of white or pale 
ochreous extending along the costa from the base to, or nearly to, 
the middle, is the distinguishing mark of costella. On a careful 
and critical examination of a very variable series, labelled 
radiatella, I detected a specimen with a faint indication of this 
costal patch; but this specimen in all other respects differed not 
at all from other examples of the same form of radiatella. I then 
proceeded to examine the blackish dots, sometimes conspicuous 
in pale-coloured radiatella, with especial regard to the spot 
situated just above the inner and towards the hind margin. ‘This 
latter I found to be identical in both insects, not only in size and 
position, but in being followed by a pale sheen, or, in some 
ENTOM.—NOV., 1886. 2M 
