1910.] FOSSORIAL WASPS OF AUSTRALIA. 259 



base of the second segment. Apical dorsal segment deflexecl, 

 elongate triangular, and finely longitudinally striated. 



Entirely ferruginous brown, with sparse grey pubescence ; the 

 mandibles and pygidial area darker ; a very small patch of silver 

 pubescence in the middle of the apical margin of the first and 

 second dorsal segments. 



Length 6 mm. 



Hob. Hermannsburg, Central Australia {H. J. Hillier). 



Well distinguished from most species of the genus by the broad 

 head and thorax ; in most of the species of the genus in which 

 the head is broad and rectangular, the thorax is very much 

 narrower than the head. 



Fam. Thynnida 



The material in this family dealt with here is mainly derived 

 from the splendid collection sent by Mr. H. M. Giles from South- 

 Western Australia to the British Museum. Some other species 

 described are from the collection of the Berlin Museum and from 

 collections sent to me by Messrs. G. A. Waterhouse and R. Illidge. 

 Mr. Giles has also furnished valuable information as to the habits 

 of the species. He says that, in spite of the minute mouth-parts, 

 the females do take food, though exclusively liquid. This, he has 

 observed in many species, is disgorged by the males and placed in 

 the mouth of the female, which is carried by the male for some 

 hours. The larger females also help themselves. In a female 

 examined for me by Mr. W. Wesche there was no trace of pollen, 

 though the specimen had been taken on Leptospermitm-blossom. by 

 Mr. Illidge ; whereas in the South- American female Spilothynnus 

 bifoiberculatus Turn, a good deal of pollen was to be found, showing 

 that the more normal mouth of the South-American females 

 is associated with a difference in feeding-habits. In several 

 cases Mr. Giles captured specimens cross-paired, males of the same 

 species being taken carrying widely different females. There can 

 here be no question as to any mistake in the observation, Mr. Giles 

 being a most careful observer. Professor Dahl observed in .New 

 Britain that the female of Thynnus serriger Sharp is to be found 

 on leaves with the mandibles wide open, probably for the purpose 

 of seizing the male. I am inclined to think that the male may be 

 used in this way as a means of transport, and that the strongly 

 developed claspers may be used in carrying the female without 

 coupling actually taking place in cases where the two are of 

 different species. On the other hand, occasional cross-pairing 

 among the more nearly allied species is not wholly improbable. 

 Mr. Giles has also observed a male of one species going into a 

 Bembex-burrow and returning coupled with a female. On digging 

 up more Bembex-hurrows he succeeded in finding another female 

 of the same species, thus showing that my suggestion that some 

 of the smaller species are parasitic on Bembex is almost certainly 

 correct. 



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