MAXILLAEY PALPI IX DIPTEKA. 



225 



The mandibles act as supports and assist in working the labella. 



The upper parts of the maxillte, which are present in Syrphus, liave aborted, leaving AS^o*^ 

 the cardines and stipites, which find use as levers, acting on the labrum and hypo-j'^."* 

 pharynx. The maxillary palpi have mostly aborted, but in many species they are,^ 

 present in a more or less rudimentary state. "When the maxillary palpi are present, 

 they are based on structures homologous with the palpifers. These are attached to the 

 stipites. The palpi are situated at proportionally the same distance from the bases of 

 the cardines as the palpi in the Syrphidse and the Empidfe (PI. 8. figs. 3, 5, 6 ; & PI. 9. 

 fig. 17). The proboscis has, on its dorsal surface, a lancet-case, the labrum, which acts 

 as a sheath for the hypopharynx, which homologizes with the lingua. 



At the base of the hypopharynx, and continuing it, is a tube, the pharynx ; this is 

 sometimes tracheated, and is well marked in this state in Calliphora and Stomoxys. 

 This tube curves upwards under the base of the labrum. 



The proboscis in the Syrphidise and the Empidfe corresponds with that in Musca, 

 except that, in their case, the labial palpi have aborted, and the lacinia^ of the maxillae 

 and maxillary palpi are present. 



Rudimentary Ilaxillary Faljn. — I shall now give a short description of the rudi- 

 mentary maxillary palpi in a few species, figuring various forms. 



Eamily Anthomyiid^, subfamily MydceincB. — PoUetes lardaria, Fabr. Palpi pyra- 

 midal in form, strongly haired, short pointed projection at extremity of stipes, palpifer 

 marked ; base i^j^ in., length -^^xi ^^- (PI- 8. fig. 13.) 



Same family and subfamily. — Hyetodesia lucorum, Zett. Very elongated, strongly 

 haired, long blunt projection at extremity of stipes, palpifer marked ; base tts^ i^-. 

 length 2^7 in. (PL 8. fig. 16.) 



Same family and subfamily. — Hyetodesia perdita, Meig. Acutely conical, well haired, 

 no projection, palpifer indistinct ; base 9^0 in., length 3^^7 in. (PI. 8. fig. 10.) 



Same family and subfamily. — Mydea impiDicta, Pallen. Broad at the base; base not 

 haired ; tapers off with a curve, where it is thickly haired ; stipes bi'oadens very much 

 at end; palpifer indistinct; base -^q in., length -^\-^ in. (PI. 8. fig. 9.) 



Same family and subfamily. — JSydrotea dentipes, Fabr. Short and thick ; thickly 

 haired, blunt projection of stipes ; base ^0 in., length 3^77 in. (PI. 8. fig. 15.) 



Same family and subfamily. — Ophyra leucostoma, Wied. Broad at the base, short and 



\ 



fio in., length 



400 



in. The cardines are 



stout, thickly haired, palpifer distinct ; base 4 ; 

 very strong in this species. (PI. 8. fig. 14.) 



Same family, subfamily IIomalomyiin<B. — Homalomyia canicularis, Linn. Very small, 

 conical in shape ; base xsVo in-> length -g\-g in. (PI. 9. fig. 28.) 



Family MusciD^. — Cyrtoneiira stuhulans. Fallen. Tubular and short ; stipes projects, 

 well haired ; palpifer fairly distinct; base ^^o i"-. length 450 in. (PI. 8. fig. 11.) 



In a very rudimentaiy form I have found the palpi in a number of species. They 

 have all very much the same appearance, so that a separate description would be 

 superfluous. I have figured four species. In most cases only a few hairs remain, but 

 in Lasiops I have found quite a tuft. 



