118 



ENTOMOLOGY. 



its having but a single pair of wings; the hinder pair being 

 rudimentary, and forming the balancers or halteres. In 

 many flies the antennas are short and 3-jointed, the last 

 joint being furnished with a bristle, which in the house-fly 

 and its allies is feathery; or, as in the mosquito and its 

 allies, the antenna? are long and many- jointed. 



Examining the house-fly as a type of Diptera in general, 



we notice that the 3-jointed an- 

 tennae, when not extended, lie 

 in a cavity in the face. The 

 mandibles and maxillae, so well 

 developed in the mosquito and 

 other piercing or biting flies, 

 are aborted, though the maxil- 

 lary palpi are present (Fig. 136, 

 mxp: Fig. 137, p). On the 



Fig. 136.— .4, front, and B, side, view ,, , , , , ' , . . 



of head of house-fly. oc, simple, other hand, the under lip, or 

 ?e U ,U' SSPSSfflS p^piH; so-called proboscis, ends in two 

 tongue; tab, labeiium. Magnified. flapg (lamella), adapted f or lap- 

 ping liquid food. The structure of the proboscis is very 

 curious. When the fly settles upon a lump of sugar or 

 other sweet object, or even upon the back of our hand 



Menzbier, M. A. Ueber das Kopfskelet und die Mundwerkzeuge der 



Zweiflugler (Bull. Soc. imp. Natur. Moscou, 1880). 

 Osten Sacken, C. R. von. Catalogue of the described Diptera of North 



America (second edition. Washington, Smithsonian lust., 1878). 



Also numerous papers and monographs published by Smithsonian 



Inst., Am. Eut. Soc., etc. 

 Scheiner, J. R. Fauna Austriaca. Fliegen. (i, ii. Wien, 1862-64.) 

 Walker, F. List of the Diptera iu the collection of the British 3Iu- 



seum (7 parts, 12mo. 1848-55). 

 Wiedemann, C R. W. Aussereuropaische zweiflugelige Insekten (2 



vols. Hamm, 1828-30). 

 Williston, S. W. Synopsis of the North American Syrphidae (Bull. 31, 



U. S. Nat. Mm Washington, 1886). 

 Dipterological notes and descriptions (Trans. Am. Ent. Soc, 



xiii.,1886). 



On the N. Am. Asilidae (Trans. Am. Ent. Soc, xi., xii., 1884-5). 



Also articles by Bergenstamm and Loew, Bigot, Brauer, Burgess, 

 Fitch, Gerstacker, Leach, McCloskie, Riley, Say, Shimer, Walsh, 



Westwood, and Willistou. 



