858 Charles Paul Alexander 



puhipennis, Erioptera (Empeda) pubescens, Gnophomyia luduosa, species 

 of Adelphomyia, the subgenus Lasiomastix of Limnophila, Bittacomor- 

 phella, certain Ptychoptera, and some species of Dolichopeza (Tricho- 

 dolichopeza) , Tipula (Trichotipula, Cinctotipula) , and so on. In most 

 crane-flies the wing veins hkewise bear long hairs, which in some genera, 

 such as Molophilus, are very long; in some species, however, the hairs 

 are so short as to be scarcely noticeable. 



The metathorax. — The only part of the metanotum, or dorsal sclerite 

 of the metathorax, which is visible is the postnotum. This appears 

 as a narrow, transverse sclerite between the mesonotal postnotum and 

 the first segment of the abdomen. The pleural sclerites consist of the 

 metepisternuin, a very small sclerite between the metathoracic spiracle 

 and the hind coxae, and the metepimeron, a small sclerite behind the 

 halteres. 



The metathorax bears the hind legs and the halteres, or balancers. The 

 halteres are usually considered as being reduced hind wings, and serve an 

 important function in flight. They lie just behind the wings and are 

 of various shapes, in some species (as Dicranomyia halterata and Gonomyia 

 fiUcauda, for example) being very long and slender and in other cases 

 being short with prominent swollen knobs. In some groups with reduced 

 wings (such as Platylimnobia) the halteres also are reduced and straplike. 

 The halteres are retained even when the wings have been practically 

 lost, as shown by the genus Chionea. 



The legs 



The legs of crane-flies are as a rule excessively elongated, which gives 

 to the group all or almost all of its common names — crane-fly (from 

 a comparison with the crane), daddy longlegs (the British name for the 

 group), and so on. The leg is made up of nine segments, designated, 

 respectively, from the body outward, as the coxa, the trochanter, the 

 femur, the tibia, and the five tarsal segments. 



The coxa. — The coxa is the enlarged basal segment of the leg, that 

 of the fore leg being called the fore coxa, precoxa, or procoxa, and those 

 of the middle and hind legs having the corresponding prefixes. In the 

 groups with great powers of flight (Megistocera, Trentepohlia, and others) 

 the coxae are very small, while in the species with reduced wings and 

 consequent need of walking (as in the genera Platylimnobia, Chionea, 



