180 Proceeding* of the Biological Society of Washington. 



tion and this also seems to be an effective barrier against 

 inbreeding; for males and females of the same brood appear 

 unable to issue simultaneously on account of the interpolated 

 larval stages of the former. 



The breeding of the specimens is not difficult, except when 

 too frequently disturbed. The larvae do not appear well able 

 to readjust their surroundings after the gallery is opened, and 

 the adherence of the skin to any smooth surface like glass has 

 prevented their being kept in thin sections between microscope 

 slides. Chips of wood kept in plaster cells have given best 

 results, but the life-history must be pieced together out of dis- 

 jointed observations and occasional thorough examinations of 

 breeding material of known origin. 



Beginning with the young larva born by the paedogenetic 

 mother larva, we have a minute white larva principally con- 

 spicuous by its long, slender legs of the carabid type — i. e. coxa, 

 trochanter, femur, tibia, tarsus and two claws. The remains of 

 the mother are usually consumed by some of her young, after 

 which all crawl away. This stage is to the species a minor 

 migratory form, securing dispersal into new parts of the log in 

 which the colony is living. After crawling out of the mother's 

 cell the young wander for a time, then start burrowing into the 

 wood again, feed a little and after a week or so moult into the 

 second form which is legless and much resembles a Cerarnbycid 

 larva, but for its odd but inconspicuous anal armature. A 

 second or perhaps a third moult must occur in this .form to 

 allow for growth of head. The larva bores through the wood, 

 packing its gallery tightly behind it with dust for some months, 

 the body appearing dark colored from the food in the alimentary 

 tract. During the latter part of this growth the eggs in the 

 ovaries of what will be the paedogenetic form become plainly 

 evident as large obliquely placed, oval, white bodies on each 

 side of the distended and dark colored alimentary tract. When 

 full fed it reverses its position in the gallery, makes a cell and 

 begins to " aestivate." Gradually the body becomes white until 

 no food is left in the alimentary tract. It then either, very 

 rarely, pupates, or usually, moults, disclosing the paedogenetic 

 form. After a period of about two weeks the young number- 

 ing from three or four, to thirty or forty, but usually about ten 

 in number are born, tail first, and begin the new generation. 



