1921.] Tillyard.—Neuropteroid Insects as Trout-food. 
271 
NEUROPTEROID INSECTS OF THE HOT SPRINGS 
REGION, NEW ZEALAND, IN RELATION TO THE 
PROBLEM OF TROUT-FOOD.* 
By R. J. Tillyard. M.A., D.Sc., F.L.S., F.E.S., Macleay Fellow, Linnean 
Society of New South Wales. 
On arrival at Auckland from Sydney on the 5th November, 1919, I was 
met by Mr. D. Miller, Government Entomologist, and Mr. H. Hamilton, 
Zoologist to the Dominion Museum, and proceeded with them to Rotorua,, 
where I met Mr. Moorhouse, in charge of the fish-hatchery in Lake Rotorua, 
and Mr. W. Hill, Resident Agent of the Tourist Department. All these 
gentlemen offered me every assistance in carrying out my investigations, 
and I desire to thank them very sincerely for their aid. I had also the 
advantage of seeing a manuscript preliminary report by Mr. W. J. Phillipps, 
of the Dominion Museum, who is studying the endemic and introduced fish 
faunas of the lakes of the Hot Springs region, and a published report on 
New Zealand Fresh-water Fisheries by Mr. L. F. Ayson, Chief Inspector of 
Fisheries. 
Three weeks were spent in the Hot Springs region, the following being 
the itinerary :— 
Nov. 7-10 : Rotorua. Visited Te Wairoa, Whakarewarewa, and por¬ 
tions of the lake. 
Nov. 11-17 : Te Wairoa and Lake Tara we ra. 
Nov. 18-19 : Rotorua. Visited Fairy Spring, Hamurana Spring, 
Lake Rotoiti, and Okere Rapids. 
Nov. 20-21 : Wairakei and Taupo. 
Nov. 22-26 : Tokaanu. 
Nov. 27 : Lake Roto-Aira. 
Nov. 28 : Waimarino. 
It was hoped that a return visit might have been arranged later in the 
season (February) in order to see the other lakes and streams of this region, 
and to study the insects in the height of summer. Circumstances, how¬ 
ever, made it impossible to carry out this plan. 
The work done in the field may be divided into two parts :— 
(i.) Examinations of the contents of trout-stomachs. 
(ii.) Collection of the larvae and imagines of neuropteroid insects from 
the streams and lakes. 
(i.) The Contents of Trout-Stomachs. 
An examination of a considerable number of trout-stomachs during 
the month of November showed a great diversity of food eaten. The green 
manuka-beetle, Pyronota festiva, was found to be the most abundant food. 
This beetle visits the manuka-bushes fringing the lakes and streams, and 
frequently falls or is blown off into the water, when it is at once seized and 
swallowed by the trout. Next in importance to this were found to be the 
* This report was prepared at the request of the New Zealand Government, and 
has been published in the Proceedings of the Linnean Society of New South Wales, 
vol. 155, part 2, 26th May, 1920, pp. 205-213. 
