THE CRANE-FLIES OF NEW YORK PART II 715 



In Tipula bicornis (Webster, 1893 b) the egg is 0.8 millimeter long by 0.3 

 to 0.4 millimeter in diameter, elongate-ovoid, with one side deeply concave, 

 the surface highly polished. The egg of Nephrotoma ferruginea is smaller, 

 with five distinct grooves. The egg of Tipula glacialis (Pokorny, 1887:53) 

 is described as being 1.2 millimeters long and only 0.3 millimeter in diame- 

 ter, cylindrical, the two ends equally rounded, the surface smooth, shiny 

 black, with faint steel-blue or purplish red reflections. In many other 

 genera of Tipulidae, especially the smaller forms, the eggs are soft and 

 whitish or nearly hyaline. In a few species the eggs take on a decided 

 green or greenish tinge. The egg of Cylindrotoma splendens is described 

 elsewhere in this paper (page 709). The egg of Ptychoptera albimana, as 

 described by Topsent (1914-16), measures 0.825 by 0.284 millimeter, 

 and is pale yellow, slightly arcuated, and with the surface curiously 

 ornamented. 



The larva 



As a rule, the larvae live in the haunts where the eggs are laid. The 

 duration of the larval stage varies from about a month in Styringomyia 

 (larva and pupa together, thirty-seven days Terry ms.) to the greater 

 part of a year in most crane-flies. Many of the smaller species of Eri- 

 optera, Ormosia, Rhaphidolabis, and other genera are on the wing in the 

 spring and again in the fall, and with little doubt are double-brooded. 

 This would make the larval existence but a few months, but still probably 

 longer than the other stages taken together. This problem of double 

 broods should be worked out carefully. It often appears that there are 

 two broods, when in reality there may be two developing generations, 

 each passing the winter as larvae, but one attaining its growth much more 

 slowly in the spring and summer and not maturing until late summer. 

 Phalacrocera and Cylindrotoma splendens spend about eleven months in 

 the larval stage (Bengtsson 1897, and Cameron 1918), while Tipula 

 paludosa spends nine months in that stage (Rennie, 1917). It is probable 

 that nearly all crane-flies in the North Temperate Zone winter normally 

 as larvae. The growth during summer, fall, and winter is very slight, but 

 in the spring it is greatly accelerated and in a month the larva may 

 attain its full growth. Larvae of Tipula ignobilis taken at Ithaca, New 

 York, on April 23, 1917, measured only 6.5 millimeters in length; on 

 May 19 they had attained their full growth of 18 millimeters and were 

 ready to pupate. Cylindrotoma splendens spends the winter as a larva, 



