Notes on the New Zealand Species of Netelia
The two species of Netelia occurring in New Zealand are easily distinguished by their colour; structurally they are very similar. Two characters that have been found to be fairly constant are the incompleteness of the outer border of the areolet (Figs. 8 and 9) and the relative lengths of the upper and lower portions of the nervellus in the hind-wing (Figs. 6 and 7). In respect to the second character, 32 specimens of ephippiatus and 39 specimens of productus collected from widely separated localities were measured and the results are presented graphically in Fig. 5; this character is easily observed and will serve in doubtful cases as a reliable criterion for the separation of the two species.
A species described by Brues (1922, p. 19) from Fiji, which is closely related to productus, shows sexual dimorphism in that the males have the aciculations of the propodeum more clearly indicated medially and by the white face and orbits as well as the larger ocelli, while the lower outer side of the areolet is more distinct. The size of the ocelli and the aciculations of the propodeum show slight variations in the New Zealand forms, but few constant differences can be detected between the sexes.
There are several specimens of Netelia that at present I am unable to place satisfactorily; in particular there is a large female collected at Manguiti, on March 8, 1916. This may be a distinct species, but I have refrained from naming it until further specimens are obtained. There are certain indications, from the material I have examined, that when more information on the biology and habits of the species of Netelia is available, the present species may possibly be conveniently separated into several well-marked sub-species, based on slight but more or less constant structural details associated with seasonal and host distribution within New Zealand.
In the case of N. productus it is of interest to record the manner in which the Nelson and Kaikohe material was collected. The Nelson specimens were collected from the windows of a house at night, the insects being attracted by the light. This material consisted of eleven females and two males. The Kaikohe specimens, comprised entirely of males, were collected by sweeping herbage and long grass during the evening just before dark. Dr. R. A. Cumber, who collected this material, observed these insects on or near the ground probably hunting for females.
Townes (1938) groups the Nearctic species of Netelia into several sub-genera. The New Zealand species belong to his typical sub-genus Netelia, but they do not appear to conform to any of his species groups included in this sub-genus, although they show affinities with the Leo group.