The Biology of the North American 
Crane-Flies 
(Tipulide, Diptera) 
V. The Genus Dicranoptycha Osten Sacken 
BY CHARLES P. ALEXANDER, Ph.D. (Cornell) 
GENERIC DIAGNOSIS 
Larva. Form very elongate, terete; integument smooth, glassy, transparent; abdom- 
inal segments two to eight with a basal transverse band or area of microscopic chiti- 
nized points on the ventral surface; segment eight with a similar band on the dorsum. 
Spiracular disk surrounded by four lobes, the lateral pair more slender than the blunt 
ventral pair; dorsal lobe very low or lacking; spiracles small, widely separated; a 
triangular brown mark on the disk between the spiracles; anal gills a fleshy protuber- 
ant ring surrounding the anus. Head-capsule compact, massive, the praefrons large 
with a few marginal punctures; externo-lateral plates very broad. Labrum large, flat- 
tened, pale; antenne two-segmented, the apical segment almost as long as the basal 
segment, narrowed to the blunt tip; mandibles with a blunt dorsal and two blunt 
ventral ‘teeth; maxille generalized in structure; hypopharynx a rounded cushion; 
mentum deeply split behind but not completely divided, with three principle teeth and 
a small lateral tooth on either side. 
Pupa. Cephalic crest low, depressed, setiferous; labrum tumid; labial lobes oval, 
contiguous; antennal sheaths ending opposite the base of the wing. Pronotal breath- 
ing-horns microscopic, represented only by tiny triangular tubercles; mesonotum un- 
armed; wing-sheaths ending opposite the middle of the third abdominal segment; leg- 
sheaths ending opposite the base of the fifth abdominal segment, the tarsi terminating 
ona level, or nearly so. Abdominal tergites and sternites each with four transverse 
rows of microscopic sete; lateral spiracles on segments two to seven. 
DISCUSSION OF THE GENUS 
The genus Dicranoptycha was erected by Osten Sacken in 1860 (Proc. Acad. Nat. 
Sci. Phila. for 1859, p. 217). The genus includes a small group of crane-flies with a 
Holarctic distribution, there being about six species in North America and two, or pos- 
sibly three, in Europe. As I have indicated elsewhere, D. signaticollis v.d.W. of Java 
is undoubtedly a species of Libnotes. Of the American species, D. germana O.S. is 
characteristic of the Canadian life-zone of northeastern America. D. sobrina O.S. is 
Widely distributed in the United States and southern Canada, usually occurring in the 
Transitional and Upper Austral life-zones. So far as known at present it is the only 
species of the genus occurring on the Pacific slope. The remaining American species 
(nigripes O.S., winnemana Alex., tigrina Alex. and minima Alex.) are Austral in dis- 
tribution, occurring in the southeastern and south central United States. A more de- 
tailed account of the distribution of the species is given in another paper by the writer 
which may be consulted (Proc. Acad. Nat. Sci. Phila. for 1916, pp. 496, 497). All of 
the known species are generally similar to one another in appearance and are: separ- 
ated by relatively slight differences of size, color and structure. 
Nothing has ever been written concerning the immature stages of this peculiar 
