108 
Psyche 
[September 
venation of the fore wings which are, in this case, also asso- 
ciated with glabrous areas of the wing surface. 
Another type of structure seen on the wings of insects 
belonging to several diverse groups are small, thickened 
spots usually deeply pigmented and frequently surrounded 
by darkened areas that show no apparent chitinization in 
excess of that on the general wing surface. 
These structures, which are known by the general term 
of nygmata, have been briefly described by Forbes (Entom. 
News, vol. 35, pp. 230-232, 1 pi. (1924)), who notes their 
presence in certain Megaloptera, Neuroptera, Trichoptera, 
Mecoptera and Hymenoptera. When examined in dried 
specimens that have been mounted in balsam, it appears 
probable that they represent glands and they may quite pos- 
sibly be moulting fluid glands as has been suggested by 
Forbes (l.c .) . In a Megalopteron (Chauliodes) they are in 
the form of minute tubercles, lying at the center of a small 
area where the wing hairs are extremely abundant and 
closely placed, causing a darkening of the wing surface 
(Fig. 4) each hair having the basal portion greatly swollen. 
In a hymenopteron (Arge) one prominent nygma in the 
second submarginal cell (Fig. 5) seems probably to be 
glandular in structure with strongly pigmented dendritic 
outgrowths apparently between the wing membranes, but 
in another more primitive saw-fly, Neurotoma, the nygmata 
are much smaller and appear to be of simpler structure. 
Still other minute structures, evidently true sensillse, 
occur on the stigma or on veins near the stigma. An ex- 
tensive account of these in the Hymenoptera has recently 
been given by Hoffmeyer. 1 
The large swelling in Phymatoptera appears to be utterly 
unlike any of these structures except perhaps those men- 
tioned in Henicospilus. Externally it gives no indication 
of glandular structure and certainly it has no visible open- 
ing. Above, it is slightly convex with the surface dull, be- 
low the surface is shining and deeply furrowed basally ( i.e . 
toward the base of the wing) by six or eight furrows run- 
iUeber Sensillen in den Hymenopteren-Fliigeln, Entom. MedeL, 
vol. 18, pp. 58-74: (1932). 
