the Gill-c/iumlers of Land-crahs, H79 



TIio fact.'', with localities, niny be shortly statt^ thus : — 



Cecarcinuft ijuadratus : from Clarion Island (Pacific). 



One specimen only examined. Very many small 

 Oiii,M>cluvta lound on and among the gill-'. 



('(irJisoma hirtipes : (a) from the Admiralty Islands (' Clial- 

 JengiT ' Collection). 



Twoont of throe specinHns examined had dipterous 

 larvte in their gill-chambers. 



(/») from Christmas Island. 



One out of throe specimens had a fragment of a 

 larva adhering to the ontsitle of it, near the lateral 

 opening of the gill-chamber. 



Gecarcoidea Idhvidii'. from Christmas Island. 



Out of three specimens ono piovided three very 

 small larva?. 



^Ir. F. W. Edwards, of the Entomological Department of 

 the British I\[useum, who has examined the dipterous hirvEe, 

 kindly supplies me with the following infoiination : — 



" Di|)teruus larva? from Caidtsoma hirtipes. — These larvae 

 are evidently Syrphida^, and apparently Ixlong to the sub- 

 tamily Eristalinai ; they differ from Eristalis in the more 

 elongated form and the lack of any obvious separation into 

 ' body ' and ' tail.' 



" Larvje from Gecarcoidea lalandii. — These are also 

 Svrphidaj, but in the present state of our knowledge it is 

 impossible to assign them definitely to any subfamily. They 

 apjx'ar to lack the (xtensile 'tail' of Eristalisy 



Wlicther these larvae ought properly to be considered 

 ] arasites of tlie crabs is, perhaps, a matter of doubt *. It is, 

 of course, possible that they arrived in their gill-chambers 

 accidentally. They may have wandered there from some 

 decaying matter uj)nn which the crabs were feeding, according 

 to their habit, or from the water of some stream entered by 

 the crabs. According to Dr. C. W. Andrews [i], Cardisoma 

 hirtipes (referred to under the name ot C. camifex) is never 

 found tar from the streams in Christmas Island, and lives in 

 burrows in the mud of the banks, and it wuul.l be rash to 



* It sbouUl bo borne in mind that there is n remote possibility that the 

 eggs were deposited upon the crabs after death, in which case the larvai 

 could not be called jarasites. 



