524 
LIST OF NORFOLK SAWFLIES. 
I have availed mj-’self. Mr. Cameron, in the ‘ Entomologists’ 
Monthly Magazine’ (vol. xiii. p. 173), gives the result of an 
inspection of Stephens’ collection of British Sawflies, now in the 
British Museum, and the number of inaccuracies in nomenclature 
which he records very much reduces the value of references from 
Stephens’ book. 
The economy of the Sawflies is extremely interesting. They are, 
in the larval state, vegetable feeders. The majority of them feed 
on the outside of the leaf. Some few are leaf rollers, some again 
mine the leaves, others form galls on the leaves of various species 
of Willow, and two or three make woody galls on the young 
shoots of Willows. 
In some species the male fly is very rare, and in a few instances 
quite unknown. The male of the common Sawfly which makes 
the galls found on almost every Willow [Nematus gallicola) is 
exceedingly rare. I was fortunate enough to breed one. The 
male of the very common Erioenmpa ovata, which abounds almost 
everywhere where Alders are to be found, is quite unknown ; and 
Mr. Cameron thinks it probable that the sex does not exist at all. 
I have hatched eggs laid by a virgin female, but did not 
succeed in rearing the larvas. Mr. Cameron and Mr. J. E. Fletcher 
were more successful, and reared the perfect fly from larva hatched 
from eggs laid by vii’gin females. I would refer any one who 
wishes to go more fully into this peculiar freak of nature, to the 
Introduction to klr. Cameron’s ‘ Monograph of British Sawflies,’ 
published by the Bay Society, 1882. 
Although not belonging to this group of insects, I should like 
to call attention to another peculiarity in the economy of a group 
closely allied to the Sawflies, viz., the Gallflies. Formerly many 
species were known only to exist as females, and, in spite of breed- 
ing by thousands, no one succeeded in rearing or taking a male. 
The round flat galls found on the leaves of the Oak were known 
only in one sex — the female. But Dr. Adler of Schleswig- 
Holstein, in 1877, announced the fact that he had discovered that 
these were only one form of a perfect species, so to speak j that 
eggs were laid by virgin females of the sjiangle galls (Neuroterus), 
produced the currant galls in the spring, which galls brought forth 
male and female insects ; the females of these currant galls again, 
later on, produced the spangle galls. In the ‘ Nachrichten ’ for 
