154 A NATURALIST IN BORNEO 



small vetch lenticular objects, dark brown in colour 

 with a paler spot situated on one side, and they have 

 no capitulum. The species of the genus Marmessoidca 

 do not drop their eggs casually, but attach them in 

 rows to leaves, and only a few, in comparison with 

 the scores of other species, are laid. They are creamy 

 white, but the upper side is covered with a black net- 

 work, and the hilar area is marked by a denser pig- 

 ment. In shape they are a long oval, and at one 

 end on the upper side is the operculum, dotted with 

 pigment except for a clear white crescent ; there is no 

 capitulum. 



Some species of Phasmidce have the power of par- 

 thenogenetic reproduction for several generations. In 

 Sarawak I kept Eurycnema herciilanea in captivity for 

 eight generations. Although no males ever appeared 

 the females laid eggs which in course of time hatched 

 out, and the larvae grew to maturity and in turn laid 

 eggs also. I noticed that the later generations laid a 

 larger proportion of eggs that never hatched out, and 

 also a larger proportion of dwarfed infertile eggs. 

 How long the race would have taken to become ex- 

 tinct in the natural course of events I cannot say, for 

 a captive monkey broke loose one day in my absence 

 and extinguished the whole brood by the process of 

 eating them one and all ; the specimens were all in 

 the larval stage, and as I had no more eggs my 

 observations came to an abrupt conclusion. The 

 male of Eurycnema herculanea has, so far as I know, 

 never been discovered, though the female is common 

 enough in collections. Here in England I have still 

 a small colony of an Indian Stick-Insect that has 

 bred parthenogenetically for several generations ; its 



