1892.] 



THE BRITISH NATURALIST. 



169 



upon the roots of the grass, and occasionally doing much mischief. 

 This is particularly the case v/ith Tipula olcracca and paludosa, the 

 larva of which two species sometimes completely lay bare wide tracks 

 of meadow land. The species of Trichocera are of smaller size, and 

 may be observed flying throughout the winter from September to 

 May, even when there is a sharp frost and the ground is covered with 

 snow, whenever there is a glimpse of warm sunshine. Dalman also 

 discovered the singular and wingless Cliionca araneoides running 

 quickly upon fallen snow in Sweden throughout the winter. 



In Britain, we have no wingless species, but the female of Tipula 

 pagana, Me\g.=dispar, Hal., and both sexes of Molophilus nter, Meig.= 

 brevipeiuiis, Curt., have the wings so short as to be quite unfitted for 

 flight. The most gaily coloured and robust species of the family are 

 those of the genus Ctenophora, the males possessing most beautifully 

 feathered antennae. The larvae of this genus, and also of Tipula 

 flavolinmta are rotten wood feeders. Most of the larvae of the genera 

 Tipula and Pachyuhina feed on the roots of grass ; those of Limnobia 

 and allied genera in fungi and decaying vegetation. 



All the larvae of this family are not, however, terrestrial, the 

 preparatory stages of several groups being undergone in water; of 

 these the genus Ptychoptera exhibits a singular departure from the 

 rest of the family, the larva being very long and worm-like, but much 

 narrowed at the posterior extremity, which is terminated by a very 

 long and delicate tube serving to convey the air to two tracheae, 

 which extend through the entire length of the body. In the pupa 

 this peculiarity is reversed, the body being terminated by five small 

 points, whilst the anterior extremity is furnished with a very long 

 thread-like appendage serving like the former, to supply air to the 

 insect, its extremity being extended to the surface. The larvae of 

 these species which reside in damp ground, or in rotten wood, have 

 not the thoracic portion so distinctly observable as in some other 

 species ; they are not furnished with false legs, but have two short 

 horns at the anterior, and several fleshy conical appendages at the 

 posterior extremity of the body; the mouth is composed of parts 

 which have some analogy to the Mandibulata. The pupae is naked, 

 with two respiratory tubes near the head, and the margins of the 

 abdominal segments are spiny, enabling them to thrust themselves 

 forward to the surface of the ground when ready to assume the winged 

 state. 



The best months for collecting the flies are the months of May, 

 June and September. The following are the species found in Dorset- 

 shire. 



80. Acypliona macula ta, Meig Generally distributed. 



81. Rhypholophiis lineatiis, Meig. Common in damp woods, appears 



