The Crane-Flies of New York — Part II 819 



Genus Dicranomyia Stephens (Gr. fork +fly) 



1818 Furcomyia Meig. Ryst. Beschr. Zweifl. Ins., vol. 1, p. lOG (nomen nudum). 



1829 Dicranomi/ia Steph. Cat. Brit. Ins., vol. 2, p. 243. 



18.30 Siagona Meig. Syst. Beschr. Zweifl. Ins., vol. 6, pi. G5, figs. 5-7. 



18.30 GInchina Meig. Syst. Beschr. Zweifl. Ins., vol. 6, p. 280. 



1854 Numantia Bigot. Ann. Soc. Ent. France, ser. 3, vol. 2, p. 470. 



Larva. — Form slender. Body nearly glabrous, abdominal and thoracic segments with 

 dorsal and ventral transverse welts on basal annuli. Spiracular disk small, the five lobes 

 indistinct but indicated, spiracles large. Anal gills four, slender. Head capsule massive, 

 of the Limnobia type. IVIouth parts almost as in Limnobia; ventral cutting edge of man- 

 dible with fewer teeth; mentum with anterior margin more transverse and with fewer 

 teeth. 



Pupa.' — Cephalic crest lacking. Pronotal breathing horns broad, in D. simulans with 

 a basal recurved hook on dorsal side, in other known species unarmed. Basal abdominal 

 auuuli with transverse welts. Dorsum of eighth abdominal segment with vestigial spiracles. 



Dicranomyia is a very extensive genus including more than two hun- 

 dred described species of usually small flies which are found in most parts 

 of the world. The immature stages, which are found in a variety of 

 habitats practically as extensive as is covered by the entire family of 

 crane-flies, range from forms that are almost strictly aquatic, thru species 

 living beneath the bark of trees, to still other species which are leaf miners. 



In Europe, Dicranomyia trinotata (Meig.) is a characteristic member 

 of the hygropetric association, the insects living on rocks in streams, 

 where they are covered with a thin sheet of water and are usually asso- 

 ciated with such insect forms as Beraea, Tinodes, Stactobia (Trichoptera), 

 Orphnephila testacea (Ruthe), Pericoma nuhila (Meig.), Dixa maculata 

 Meig., Oxycera pulchella Meig., and other Diptera. The larva is cylin- 

 drical, measuring from 10 to 11 millimeters in length and from 1.5 to 

 2 millimeters in diameter. The dorsal surface is greenish mottled with 

 darker, the ventral surface brighter. The larvae live in loosely spun 

 silken cases in which they pupate. The pupae are about 10 millimeters 

 long, and live in cocoons which are almost horizontal in position. The 

 mature pupa breaks thru the cocoon by means of its sharp-edged breathing 

 horns, the adult then creeping forth and leaving the cast pupal hull behind. 

 (Thienemann, 1909:64-65, and Grunberg, 1910:29.) 



Dicranomyia dumetorum Meig. lives in decaying, principally deciduous, 

 wood. Winnertz (1853) found it in large numbers in a decaying beech 

 tree, associated with Bremia cilipes (Winn.), 



