4 
‘ 
BOTH 4 
5 le 
© Mr Fe W, Edwards on British Limnobiidae. 205 
vi. 1915 (Atmore), and Mr. Collin tells me he also possesses 
the species. The name is a manuscript one bestowed by 
Verrall; the type specimen is the male from King’s Lynn. 
L. decemmaculata Lw. This appears to be widely 
distributed, though nowhere common. I have seen 
examples from Nethy Bridge (Lamb), Leigh Woods, 
Bristol (Hudd); North Herts. (7. W. E.); South Herts. 
(Austen) and Henley-on-Thames (Scott), Small specimens 
have a rather strong resemblance to Dicranomyia dumetorum 
especially on account of the silvery frons, but the venation 
and other characters will distinguish them. 
Heutus (Rhamphidia). 
For conformity with the rules of zoological nomenclature, 
the name Helius (St. Fargeau and Serville, 1828) must 
replace Rhamphidia (Meigen, 1830). Since Riedel has 
recently revived the alternative name Megarhina some 
explanation is necessary as to why this name is rejected in 
favour of Helius. According to Kertesz’s catalogue, both 
these names were published in 1825 (Hncycl. Method. 
Zool. x, pp. 585 and 831), but, as shown by Sherborn (Ann. 
Mag. Nat. Hist. (7) xvi, p. 577), the date of the second half 
of the volume in which they appear was really 1828. In 
1827 Robineau-Desvoidy had proposed Megarhinus for a 
genus of Culicidae, and for this (implied) reason St. Fargeau 
and Serville altered their name Megarhina to Helius in the 
index. Although the nomenclature rules allow the reten- 
tion of two generic names differing only in termination, 
and I have elsewhere argued in favour of this, it would 
obviously be very inconvenient to have a Megarhinus in 
Culicidae and a Megarhina in Limnobiidae. The name 
Megarhina is therefore rejected ; this course can be justi- 
fied by the fact that both Megarhina and Helis were 
published on the same date by the same authors, whose 
desire was clearly that the latter should be used. Helius 
should not be considered preoccupied by Helia (Hiibner, 
1816, Lepidoptera). 
I cannot agree with Verrall and de Meijere that the three 
described European species of this genus should be lumped 
together. We certainly seem to have three distinct species 
in this country, none of which can be satisfactorily identified 
with the descriptions of either H. longirostris or K. inornatus, 
nor yet with the Japanese species recently described by 
