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ANNUAL REPORT OF NEW-YORK 
crest upon the hind part of its thorax. In both these species 
the hind margin of the wings is entire and not scalloped as they 
are in the genus Gastropacha, and their wings are more thin, 
delicate and semi-transparent. In G. Americana the second vein 
which is given oft' from the outer side of the outer principal 
vein of the fore wings forks forward of its middle and both its 
branches terminate in the outer edge of the wing forward of its 
apex. In these two species the same vein forks much beyond 
its middle, the two branches diverge much more strongly, and 
both end in the hind margin of the wing, rather inside of the 
apex, the tip of the wing here being rounded and not forming 
an angle as it does in the former species. Such differences for¬ 
bid our associating these insects together in the same genus. 
And as their deceptive appearance is one of their most promi¬ 
nent characteristics in each stage of their lives, the generic name 
Planosa (Greek a deceiver,) or in English, the cheaters, 
may appropriately be given to the Velleda and the species which 
we have here described. The best distinctive name for the lat¬ 
ter will be that of the tree which it infests. We therefore pro¬ 
pose calling it Planosa Laricis , or the Larch cheater. 
From one of the four cocoons mentioned above, came five 
parasitic insects, which had destroyed the pupa. These gnawed 
their way out of the cocoon at short distances from each other, 
each making a round hole, the edges of which were rough and 
jagged. They were all females of a pretty species of Ichneu¬ 
mon fly (Family Ichneumonioe Order Hymenoptera) 0.30 long, 
ol a black color with the abdomen and legs tawny red and the 
hind feet, scutel and a band on the middle of the antenna; 
white. They pertain to the genus Phygadeuon of Gravenhorst, 
which genus is distinguished by having a depressed abdomen nar¬ 
rowed at its base into a slender stalk or petiole, a protruded ovi¬ 
positor, the joints towards the base of the antenna; somervhat 
long and the small cell in the middle of the fore wings with five 
sides. This genus embraces a number of described species, most 
of which have the abdomen red or red and black, with the scu¬ 
tel also black and not pale as we find it in the present instance. 
This insect may be named 
