116 A NATURALIST IN BORNEO 



but, as we have already seen, orientalis may have 

 originated in Europe, and it is certain that australasice 

 is only a rare immigrant to Australia, and I believe 

 that tropical Africa or perhaps South-Eastern Asia was 

 its original home. 



In Sarawak P. australasice was a serious Museum pest, 

 for it devoured labels, the covers of books and any- 

 thing with starchy or sugary constituents. Con- 

 sequently I used to regard with a benevolent eye the 

 presence in the Museum of a certain small Hymen- 

 opterous insect, Evania ; this little creature has an 

 absurd triangular and flattened abdomen suspended 

 from a slender waist, and it deposits its eggs in the 

 horny egg-case of Cockroaches. These egg-cases, or 

 oothecae, have been compared in appearance to Glad- 

 stone bags : the comparison is not very apt, but it 

 serves to illustrate the fact that they are hollow, and 

 made up of two halves which, when the contained 

 young are ready to emerge, open along the top of the 

 case. By means of her cleaver-like abdomen the 

 Evania is able to prise open the egg-case of the cock- 

 roach at the line of closure, and then, thrusting in 

 her ovipositor, she deposits her eggs or an egg on 

 the eggs of the Cockroach, which are later devoured 

 by the larvae of the Evania. 



The egg-case of the Cockroach is formed inside the 

 body of the mother, and when ready and full of eggs 

 it is in many species partially extruded and carried 

 about for several days until a safe hiding-place is 

 found for it. Thus the little cosmopolitan species 

 Phyllodromia germanica forms a long flat leathery case, 

 which is carried about extruding from the apex of the 

 abdomen till just a few hours before the contained 



