FAM. GEOMETRID/E 187 
We have not been able to study much material in this genus. and are not sure about its stability. 
It differs only from Hydaía in the very brief anastomosis (or non-anastomosis) of C of the hindwing, 
but inasmuch as even in Hydaía this varies somewhat (e. g. in fovera we have found the anastomosis 
much weaker in the cf than in the Q) it would not be surprising to find that some Q Q of Prohydata 
upset the distinction altogether. We have not seen Schaus' type-species, which is said to have the palpus 
« short », and our characters are drawn chiefly from proficiens. 
Type of the genus : Prohydata apicata, Schaus (1910). 
Geographical distribution of species. — Neotropical, 
I. P. aficala, Schaus. Iolivia. 
Prohydata apicata, Schaus, Trans. Amer. Ent. Soc. Vol. 27, p. 251 (19ot). 
2. P. vitrearia, Schaus. Venezuela. 
Prohydata vitrearia, Schaus, Trans. Amer. Ent. Soc. Vol. 27, p. 251 (1901). 
3. P. fellucidaria (Dognin). Ecuador. 
Racheospila pellucidaria, Dognin, Le Naturaliste, Vol. 14, p. 206 (1892). 
4. P. stigmatica (Warren). Costa Rica. 
Hyalorrhoé stigmatica, Warren, Novit. Zool. Vol. 11, p. 21 (1904). 
5. P. brunneopicía (Warren). Peru. 
Hydata brunneopicta, Warren, Novit. Zool. Vol. 14, p. 203 (1907). 
6.- P. latifasciata (Warren). Peru. 
Hydata latifasciata, Warren, Novit. Zool. Vol. 14, p. 203 (1907). 
7- P. beneficia, Warren. Upper Amazon. 
Prohydata benepicta, Warren, Novit. Zool. Vol. 16, p. 84 (1909). 
8. P. aurata, Dognin. Colombia. 
Prohydata aurata, Dognin, Hét. Nouv. Amér. Sud (1), p. 21 (1910). 
9. P. frojiciens, Prout. — Pl. 5, Fig. 5. Colombia. 
Prohydata projiciens, Prout, Ann. Mag. Nat. Hist. (8). Vol. 6, p. 235 (1910). 
10. P. auster, nov. sp. 1), Prout. S. E. Brazil. 
I37. GENUS HYDATA, WALKER 
Hydata. Walker, List Lep. Ins. Brit. Mus. Vol. 26, p. 1621 (1862). 
Characters, — Face smooth. Palpus smooth, slender, moderate to very long. Tongue present. 
Antenna in ci bipectinate to about two-thirds with moderate to long branches, in Q minutely ciliated. 
Pectus slightly hairy. Femora glabrous. Hindtibia in c sometimes dilated with hair-pencil and terminal 
process, in both sexes with all spurs developed. Abdomen not crested. Frenulum in cj slender, some- 
times colourless, arising from before basal expansion; in Q wanting. Wings more or less hyaline. 
Forewing with costa slightly or moderately arched, apex rather acute, termen rather straight anteriorly, 
curved or bent in middle, becoming rather strongly oblique, cell nearly one-half, DC incurved, 
becoming strongly oblique, SC! from cell, anastomosing with C, sometimes becoming coincident, 
SC?5 long-stalked, SC? given off after SC*, R! separate or almost connate, R? from above middle of DC. 
M! rather widely separate; hindwing with apex rounded, termen very slightly or strongly toothed 
1| Prohydata auster, nov. sp. — 9, 2o mm. Head green, between antenn:e white. Antennal shaft white. Thorax and abdomen pale 
green above, white beneath. Wings shaped and marked nearly as in s/Zgwzafica, Warren. Forewing pale yellow-green, thinly scaled, the markings 
opaquer olive-green, but indistinct, except in certain lights, consisting of : a patch at base, its margin outangled on M ; a thick antemedian line, 
from costa just beyond one-third to inner margin at one-half, forming two curves, with a strong angle at the origin of M?, posterior half the thicker; 
a very large, slightly curved cell-spot; a thick, slightly interrupted curved line from costa at about three-fourths, the outward curves being in middle 
and at inner margin (where it becomes still thicker); a faint slender line between this line and the cell-spot, following the same course; vague sug- 
gestions of large spots on termen; in some lights the whole costal area also appears darkened; hindwing similar, but with a large blotch on inner 
margin in place of antemedian line, and a quite small, conspicuous cell-spot. Underside whitish, forewing feebly marked, hindwing unmarked, Sao Paolo, 
S, E. Brazil (E. D. Jones). Type in coll. Brit. Mus. Distinguished from s/Zg»a//ca by having truly pectinate antenna (the pectinations about three times 
diameter of shaft); palpus less long than in most of the allies, very slender, the third joint excessively so (but somewhat damaged); SC! of forewing 
running into C. 
