784 CHARLES Paut ALEXANDER 
of prominent black spots converging behind. Mandible stout, with a single powerful oute 
tooth. Mentum bilobed, anterior margin not comblike. Color of body, rusty red. 
Pupa.— Right pronotal breathing horn very elongate; the left very small and short, 
subdegenerate. Fore tarsi overlying middle tarsi. Tubercles on abdomen very long, locate 
on broad transverse bands of chitin, each tubercle with a star of four or five spines surroundin 
the apex, which bears a long seta. 
The genus Bittacomorpha, as here restricted, includes but two species 
the genotype, B. clavipes (Fabr.), and B. occidentalis Ald. of wester 
America, concerning the biology of which nothing has been recorded 
The literature on the immature stages of Bittacomorpha clavipes is sum 
marized under the family account (page 773). 
Bittacomorpha clavipes (Fabr.) 
1781 Tipula clavipes Fabr. Spec. Ins., vol. 2, p. 404. 
1835 Bittacomorpha clavipes Westw. London and Edinburgh Phil. Mag., vol. 6, p. 281 
Bittacomorpha clavipes, the ‘‘ phantom crane-fly,” is a common an 
widely distributed species thruout North America east of the Rockies 
It is easily recognized by the black-and-white-banded legs, with thei 
conspicuously enlarged and swollen metatarsi. The species is ver 
characteristic of alder swamps and the wet margins of ponds. While i 
copulation the insects often fly, the female ahead, the male trailing o 
behind like the tail of a kite. When they alight on a plant stem, th 
female is invariably uppermost, the male often hanging free with non 
of its feet on a support. The swollen metatarsi are almost completel 
filled by the tracheae, and these serve to buoy the insects as they drif 
about in the wind. Brues (1900) describes these peculiar tracheal dilatio 
in detail. He says, in part: 
When flying, Bittacomorpha uses the wings scarcely at all, relying in great measure upo 
wind currents for transportation. The legs are exceedingly light, as the exoskeleton is thi 
and delicate, and encloses practically no tissue which can serve to increase their weight 
In a letter from Dr. J. G. Needham, dated September 27, 1917, valuabl 
data on this habit of drifting are furnished, as follows: 
Yesterday while crossing the Fall Creek bridge near my home on Cornell Heights, I made 
observation on Bittacomorpha that interested me greatly. A breeze was blowing up the gorg 
and on the breeze a Bittacomorpha was drifting rapidly upward in the usual flight attitud 
with broadly outspread legs, the swollen metatarsi hanging vertically, all phantom-like 1 
slenderness and in strongly contrasting black and white. It came up from helow the lev 
of the rail, swept past within two feet of my face, and passed on upward with the breeze unti 
lost to view, perhaps 100 feet higher than the bridge, and much farther upstream. Sine 
