4 
The N.Z. Journal of Science and Technology. [Jan. 
Summary. 
The present desire to utilize New Zealand vegetable dyes in connection 
with the home spinning of woollen goods, and the abundance of the species 
of Coprosma and the large size of their roots compared with madder-roots 
used in commerce, have suggested to the author that the economic as well 
as the scientific aspect should be investigated. Preliminary tests show 
that there is reason to believe that dyes closely similar to if not identical 
with those of madder are to be obtained from Coprosmq, and the matter 
is accordingly being made the subject of research. 
A New Fungus-gnat which fertilizes Corysanthes oblonga Hook. 
By David Miller, Weraroa. 
This species of fungus-gnat (fam. Mycetophylidae) was captured after con¬ 
siderable trouble by Mr. G. M. Thomson, F.L.S., while on a visit to Dawson 
Falls at Mount Egmont during December, 1916. 
Two females were sent to me, one of which was found 
in the flower of Corysanthes ohlonga Hook., and still 
had the dorsum of the thorax covered with the pollen 
of this orchid. I have taken the liberty of naming 
this species after the collector. 
Exechia thomsoni n. sp. 
Head fuscous, the antennae and mouth-parts 
tawny ; dorsum of thorax fuscous without markings, 
the pleurae fuscous posterior to the wing articula¬ 
tion but tawny anteriorly. Legs tawny, but the 
tarsi and apices of the femora fuscous ; fore pro¬ 
tarsus 1*23 the length of the tibia. Wings dusky 
hyaline, the auxiliary vein short and evanescent at 
apex. Abdomen narrowed at base, the 2nd segment 
longer than the others ; segments 1 and 2 dark tawny, the remainder 
fuscous, each segment with a darker band across the posterior margin. 
Length, 3-5 mm. 
In the diagram the position of the posterior tibia and tarsus is reversed. 
x 5. 
A Systematic Examination of the Refractory Clays of the Canterbury 
District, with Special Reference to their Use for Firebricks and 
Furnace-linings. 
By H. V Rowe, National Research Scholar, Canterbury College. 
A report bearing the above title was prepared by Mr. Rowe after twelve 
months’ tenure of a National Research Scholarship. As the research was 
left in an incomplete state, the Chairman of the Research Board of Canter¬ 
bury College did not recommend it for publication. The report was referred 
by the Education Department to the Board of Science and Art, and it was 
decided to deposit it in the manuscript series of the Dominion Library, 
Dominion Museum, where it may be consulted on application to the 
Director. [Ed.] 
