diptehous family pantophthalmid^. 565 



boai'd the Cable S.S. Faraday, shows a considerable number of 

 what is evidently the same pseudo-parasite on the dorsal surface 

 of its abdomen, while many instances of similar infestation in 

 the case of specimens of other species of Pantophthnlmidje are 

 noted below. Since therefore, even among the limited series of 

 these flies available to the author for examination, representatives 

 of various species are infested in this manner, it would seem that 

 for some reason members of this family are peculiarly subject to 

 to invasion by this Acarid. The author's colleague, Mr. A. S. 

 Hirst, F.Z.S., to whom the mites have been submitted, has 

 kindly supplied the following note: — "The pseudo-iDaiasites are 

 nymphs of a species of Trachytes, a Gamasid mite, and presumably 

 are predatory forms, possibly feeding upon small mites or insects 

 inhabiting the tunnel of the fly-larva. This habit of attaching 

 itself to an insect host is no doubt of benefit to the mite, by 

 Avidening its area of distribution." 



Pantophthalmus frauenfeldi Schin. 

 Acanihomera frauenfeldi Schiner, Ileise der osterreichischen 

 Froaatte 'Novara' um die Erde, Zool. Theil, Bd. ii. Di])tern, 

 p. 78 (1866). 



Of this species, the National Collection possesses a $ from 

 Bogota, Colombia {ex coll. — Stevens, 1856), in which country the 

 type was obtained ; and a second $ , from Peru {ex coll. J. M. F. 

 Bigot; presented by J. E. Collin). The latter specimen, with 

 the type of Acanihomera crassijyalpis Macq. { — RhajMorliynchus 

 planiveniris Wied.), and two other $ $ of Rhajjhiorh'ynchus 

 planiventris Wied., stood in the Bigot collection above the label 

 ^'■Acanihomera crassipalpis, Macq., n. sp. $ ," in Macquart's 

 handwriting. 



Including the facial beak and ovipositor, the original Museum 

 specimen measures just over 31 mm. in length, instead of 35 mm., 

 which is the length of the type (also a $ ) as given by Schinei-. 

 The total length of Bigot's example, measured in the same Avay, 

 is 32 mm. 



In the Hope Department, University Museum, Oxford, there 

 is a solitary $ of F. frauenfeldi from Macas, Ecuador (purchnsed 

 from Stevens, 1862). The dimensions of this specimen, which is 

 veiy much larger than the examples in the National Collection, 

 are as follows: — Total length, including facial beak and ovipositor, 

 42-25 mm.; greatest width of abdomen (across hind margin of 

 second tergite) 16-25 mm. ; Aving-expanse 74-6 mm. The teiminal 

 segment of the palpi in the Oxford specimen is slender, straight 

 and cylindrical, whereas the corresponding segment in the British 

 ]\luseum 2 fi'O"^ Bogota is curved outwaids at the tip and 

 distinctly swollen towards the base; in the $ from the Bigot 

 collection the palpi are damaged. 



Two nymphs of the usual species of Gamasid mite {cf. remarks 

 under F. tahaninus above) are visible on the dorsum of the 

 abdomen of the $ from Bogota. 



37* 



