24 THE CANADIAN ENTOMOLOGIST. 



large family is reared, in which eggs, larvfe of all stages of development, 

 pupae, and young and old adults are found crowded promiscuously in leaf- 

 like brood-chambers, which are continually broadened or extended by the 

 adults and possibly by the larvae, to make room for the increase. It 

 appears that the brood-chambers are broadened and extended by the 

 adults, and that the borings, mixed with the fungus, are softened and 

 furnish additional food for the larvae and young beetles.' 



Mr. Hubbard records the discovery of a death chamber, or a kind of 

 catacomb, in which the dead mother beetles and other dead friends or 

 foes of a large colony are consigned by the survivors. In some fresh 

 specimens of galleries before me (Plate 3, fig. 2 b b), I find the same 

 thing, but it appears that in addition to a resting place for the dead, it is 

 also utilized for the disposal of all objectional and refuse matter, which, 

 owing to the crowded condition of the chamber, cannot be conveniently 

 expelled from the entrance. One of the males found in this set of 

 chambers was excavating a burrow in the mass of material in the death 

 or garbage chamber. Whether he was excavating his own tomb, or simply 

 providing bachelor quarters, I cannot say. 



The proportion of males in this, as in all other species of the genus 

 Xyleborus, is remarkably small. There are usually not more than three 

 males in the largest colonies, or groups of brood-chambers. It would 

 appear from observations made by Swiner and Eichhoff in Germany, and 

 the numerous colonies I have examined in this country, that there is, on 

 an average, about one male to twenty females. The males have no wings, 

 therefore probably do not leave the brood-chambers, but remain with the 

 over-wintering colony until all have emerged in the spring. They are 

 then left to be smothered in overabundant ambrosial food, or to the 

 tender mercies of predatory insect enemies which had previously been 

 prevented from entering the brood-chambers by one or more female 

 sentinels at the entrance. A few females may emerge from time to time 

 during the summer to start new colonies, but from the excessively crowded 

 condition of the brood-chambers during the fall and winter months, it 



I. Note, — In a brood-chamber before me just cut from a near-by apple tree, I find 

 a pupa minus an abdomen. No predaceous enemies can be found, but two or three 

 half-grown larvae are in such a position as to make the circumstantial evidence quite plain 

 that they are to blame for the mutilation. The remaining portion of the pupa is in a 

 normal condition, which would indicate that the attack had been recent and when the 

 victim was alive. This would also indicate that the helpless pupa may furnish food for 

 the larva in case of a scarcity of ambrosia, or that they may be thus disposed of to 

 prevent an overcrowded brood-chamber. 



