1915] Cocoons Among Ants 337 
in dry, open, sunny places and containing roomy chambers in 
which the black cocoons are often visible from outside the nest. 
I saw many nests of these ants in Queensland, especially in the 
environs of Brisbane, Townsville and Kuranda. In Kuranda 
I also found several species of Leptogenys of the subgenera 
Lobopelta and Odontopelta (contgera Mayr, ebenina Forel, 
diminuta Forel and its var. yarrabahna Forel and turneri Forel), 
which had very dark brown cocoons. These ants nest under 
stones and logs, but they seem to be very restless and one 
occasionally comes upon colonies moving to new nesting sites. 
At such times they carry their cocoons concealed underneath 
their bodies and between their legs and not held out in front as 
in other ants. It would seem that this concealment of the 
cocoons under the body is another devise for protecting them 
from the too direct rays of the sun. In this connection I may 
say that our single North American species of Lobopelta (L. 
elongata Buckley of the Gulf States) has brown cocoons, darker 
than those of our other ants, but paler than those of the 
Australian species. Other Australian Lobopeltas, such as L. 
mutans, which has small eyes and lives in rotten logs in the dark 
jungle, have pale brown cocoons. It is also worthy of note that 
winged females do not exist in Rhytidoponera sens. str. and 
Leptogenys.. In the latter genus the female is wingless and 
almost exactly like the worker, and the egg-laying function in 
Rhytidoponera 1s very probably usurped by fertile workers as in 
Diacamma. Whether or not this correlation between the 
presence of black cocoons and the absence of differentiated 
females is more than a mere coincidence can be decided only by 
further investigations. 
The fact I wish to emphasize is that the larvee of Diacamma, 
Rhytidoponera and Leptogenys, while temporarily buried in the 
soil by their worker nurses, are able to spin cocoons preadapted 
in color to furthering their own development as pupz by 
utilizing the heat of the sun and simultaneously excluding the 
deleterious light and ultra-violet rays. This utilization, more- 
over, is possible only through the co-operative agency of other 
individuals, z. e., the worker nurses of the colony. The natural 
selectionist will probably insist that the origin of this melanism 
in an inert and extraneous pupal envelope can be explained 
only on the assumption of a survival of chance variations in the 
color of the silk spun by the larvae. The possible contention of 
