INTRODUCTION. 



^ 



that it is hardly possible to determine the intermediate stages, 

 especially as larva' ami pupic do not stand disturbance so 

 well as those of Rutclidie for instance. The parents remain 

 witli their brood until all have i)upated and with the pupae 

 until these have become adult and must even attend to the 

 freshly developed beetles, which take some time to become 

 hardened and their organs so fully mature that they are able 

 to feed themselves. In January and February complete 

 families are connnonly found together still, even close together 

 in the same gallery, the elders only distinguishable from the 

 young by the worn teeth of the front tibiae, scanty hair, missing 

 tarsi, etc. . . . 



Common as the beetles are in old timber, one rarely sees 

 them in the open ; I believe there were not half-a-dozen times 

 when I found individuals upon the ground or crawhng on old 

 logs in the forest. Usually one finds only one family in a 

 tree-trunk, often together with larva? of other Lamellicornia, 

 but rarely are several families of a species together and I 

 never found different species in company. I only once saw 

 a Passahd in flight — the fhght is slow and heavy." 



W. M. Wheeler, ui liis book upon ' The Social Life of Lisects ' 

 (1923, p. 27), states that his own observations, made in Central 

 and South America, Trmidad and Australia, confirm those 

 of Ohaus, and 1 have been informed by a well-known entomo- 

 logist, Col. F. C. Fraser, that he has on various occasions 

 found in India Passahd famihes consisting of two adults 

 and a number of larvae. The precise interpretation of the 

 facts observed must, however, be regarded as not yet fuially 

 settled. In a careful review of the subject (' Uber die Biologic 

 der Fassaluskafer '), II. Heymons, who studied the insects in 

 the same regions as Dr. Ohaus, contends that there is no 

 reason to believe that parental care is actually exercised or 

 that the hfe-history of these uisects differs in any important 

 respect from that of other wood-feeding beetles. From an 

 investigation of the contents of the ahmentary canal he 

 concluded that the larv» were capable of assimilating and 

 digesting woody material in the raw state, and were not, as 

 supposed, dependent upon predigested food. Heymons' 

 observations relate chiefly to Fassaliis interstitialis in South 

 Brazil. Experiments with the North American species, 

 Popilius disjunctus 111. {=Passalus cornutusV.), made by a 

 group of students of Duke University, North Carolina, and 

 described by them in ' The Ecology of Passalus cornuius, 

 Fabricius, a beetle wliich lives m rotting logs,' by A. S. Pearse, 

 etc. (Ecological Monographs, 193G, p. 455) led to the 

 conclusion that, although well-growii larvae could be reared 

 independently upon rotting wood, young newly-liatched 

 specimens required material previously dealt with by the 



