710 Charles Paul Alexander 



of the measuring worms (Geometridae) , progression being accomplished by the aid of the 

 mandibles and the ventral tubercles, or pseudopodia. In a quiescent condition the thoracic 

 region of tlio body has a noticeable humped appearance. The fully grown larvae are very 

 sluggish and inactive. When disturbed they relax their hold on the leaf surface and fall 

 to the ground. Altho several hundred adults were reared, not a single parasite was discovered. 



Before pupation the larva attaches itself firmly to the surface of the leaf or to the leaf 

 petiole, by means of its anal pseudopodia. The skin splits transversely behind but is only 

 partially sloughed off. The head, the thorax, and the first four abdominal segments of the 

 pupa are exposed, but the apex of the abdomen remains encased in the larval skin, tl>e 

 terminal part of which, collapsed and wrinkled, is attached to the leaf surface. Pupation 

 may take place on either the upper or the lower surface, but it occurs oftener on the former. 

 If pupation takes place on the petiole, it is generally at the axil. In the breeding cages the 

 duration of the pupal period was found to vary from six to ten days. 



When the adult first emerges it is of a pale green color, which is gradually replaced by the 

 black and yellow of the fully colored insect. From one and one-half to two hours are required 

 for the adult to emerge. After emergence is completed, the fly rests for a short period 

 until the cuticle hardens and the wings expand. It seems that the adherence of the larval 

 skin to the pupa is necessary for the emergence of the adult, at least in many cases. There 

 appears to be a large disproportion of females over males, this sometimes being as high as 

 five to one. Since a single male may copulate with several females, this disproportion ia 

 not so serious as it appears at first sight. 



LIFE ACTIVITIES OF CRANE-FLIES 



The adult 



Emergence. — Emergence from the pupal hull may require but a few 

 seconds (as described for GnophomyiabyHyslop in Zz7i., the whole operation 

 requiring but eight seconds), or it may take several hours. The emergence 

 of the strictly aquatic genus Antocha has not been observed, but it must be 

 practically instantaneous as in Blepharocera and the lotic caddice flies. 



Mating.- — In several widely different species, the females as they emerge 

 from the pupal hulls are at once seized in copulation by the males altho 

 they are still callow and uncolored. Mik (1882 b: 40, and 1886 a) discusses 

 this curious condition in considerable detail. In all the cases that are 

 known to the writer — Dicranomyia irinotata, Discobola caesarea, and 

 Cylindrotoma distinctissima (Mik, 1886 a, the last-named also cited by Mik, 

 1882 b), Liogma glabrata (Miiggenberg, 1901), Tipida rufina (Giard, 1895), 

 and Tipula ultima (Caudell, 1913) — the abdomen of the female is 

 elongate, flabby, and nearly colorless. In Dicranomyia trinotata the 

 females scarcely have time to remove their legs from the pupal sheaths 

 before they are seized in copulation. In other cases the males emerge 

 before the females and wait beside the pupae for the emergence of 

 their mates, when they at once seize them in copula. In most species 

 of Tipula the males, when seeking the females, progress by a fluttering 



