324 
PA LUSTRA. By Dr. A. Seitz. 
etc., nor any genera at all represented in the Old World; much rather some species, having hitherto been dealt 
with as congeneric with the Palustra, could yet be eliminated. — The head, particularly in the 9, is very much 
lowered, so that, on being seen from above, it does not project beyond the immense thoracic wool. Proboscis 
absent, palpi very small, turned directly downward. £ antennae with 2 rows of long teeth, in some almost 
the longest found in the Arctiids at all. The dense hairing of the thorax is sometimes shaggy or covers the 
whole thorax (burmeisteri) , wings large, also the hindwings broad, with a short discocellular scarcely projecting 
beyond the middle of the wing; the discocellular forms a sharp, rather acute than obtuse angle. 9 species are 
known. 
burmeisteri. P. burmeisteri Berg (41 f, g) is one of the largest Arctiids in America, unicolorously dark brown, with 
a blackish cell-end spot, the forewing besides with a double, postmedian nebulous band. $ little lighter than 
the <$, with a blackish abdomen and ochreous-yellow anal wool. — Larva large, stout, blackish-brown; the 
animals never rest on the surface of the water, but always about 10 to 15 cm below it on Potamogeton and 
other water-plants. The air needed for breathing is held fast by the dense hair on the larva, which, thereby 
receives a lustrous silvery cover. In order to renew this air, the larva sometimes comes to the surface; this 
is also done in order to swim over to another food-plant to which it is reported never to creep over below the 
water. According to Gunther’s observations the larva, in being bred, must sometimes have running water, 
lest it perishes in the skinning. The larva is dark, densely haired, the dorsal brushes in the early stage brownish, 
later on pale yellow. In spring (November) the pupation takes place. Then the larvae are seen swimming up 
the stream in numbers, in order to go into the small brooks and the drains (so-called Canadas) traversing the 
pampas everywhere, where they leave the water for the sake of their pupation. According to observations 
by Willy Lehr (Baltimore), the larvae prefer projecting parts on the banks, where they mostly attach their 
downy spinnings on Stipa- and Carex-grasses. They often pupate gregariously (Tor 8 together), but the cocoons 
are spun in such a way as to be easily separated without being torn. The $2 having crept out after few weeks 
keep sitting on the web where they also often deposit the eggs which are wrapped into the dense, downy anal 
wool of the 9- Sometimes one $ sponges upon another depositing its own eggs in the downs of the eggs of the 
other. A remarkable fact is that the gluttonous, insectivorous fish Heros facetus Jen., which greedily devours 
the imagines of Pcdustra, disdains the larvae. The species is distributed across Uruguay and South Argentina; 
local, but in some places common. 
a films. 
ockcndcni. 
id a. 
P. affinis Bothsch. is nearly exactly like burmeisteri, but the thorax is of a darker brown, the collar 
and hairing of the abdominal base yolk-coloured. From the Organ Mountains in Brazil. 
P. ockendeni Bothsch. (41 g). Also like burmeisteri , but the tegulae and the anal tuft are golden yellow 
and on the forewing of the only specimen known, a 9, the postmedian transverse stripe is indistinct. Peru. 
P. vivida Bothsch. (41 h) resembles a small burmeisteri, but the abdomen is ochreous-yellow,. in the 
$ with a series of blackish-brown dorsal spots, in the 9 with dark bands; in the also the whole basal half of 
the hindwing is of a bright ochreous yellow; in the 9 the disc of the hindwing is lighter greyish and somewhat 
diaphanous. 
palmer]. 
P. palmeri Bothsch. (41 g) is smaller than the preceding, body and wings quite unicolorously dark 
sooty brown, except the scarcely noticeably darker cell-end without any markings at all. Colombia. 
haenschi. 
P. haenschi Bothsch. (41 g) is nearly exactly like burmeisteri, but the 9 shows a transverse band 
shaped brightening beyond the middle of the wing. — The larva is black, with rows of black, prick-shaped 
bristles. On the dorsum of each ring there is a transverse brush of dense, short, soft hair of a bright chestnut- 
brown colour. 
laboiilbeni. P. laboulbeni Bar {= argentina Berg) (41 i). Light yellowish-brown, only about half the size of 
burmeisteri, forewings with dark ante- and postmedian, as well as antemarginal nebulous lines, and with a 
dull darker cell-end spot. — Larva with tufts of short bristles, and on the dorsum of each segment with a reverted, 
black, above rufous tuft. On Mayaca fluviatilis on which it feeds under the water. On being touched, the larva 
rolls up like most of the Arctiid larvae. Cocoon blackish, with interwoven larval hairs. South America, distributed 
in the east. 
fostcri. P. fosteri Bothsch. (43 a) somewhat resembles laboulbeni , but it is more stretched, the forewings 
lighter and quite unmarked; from Paraguay. 
ajotlac. P. azollae Berg (41 i) is Mill smaller, the hindwings in the golden yellow like the abdomen, with 
a reddish tint and dark margins; forewings as well as thorax dark brown, with still darker markings. Argentina. 
tenuis. P. tenuis Berg (41 e) greatly resembles Mallocephula latior (41 d), but it has deeper red-brown forewings 
and faint nebulous spots in the hindwing. The abdomen is orange-yellow like there, though without any black 
dorsal bands. 9 with fully developed wings. Argentina. 
