The Crane-Flies of New York — Part I 841 



THE PUPA 



The pupal stage is of short duration, usually a week or two, and is 

 spent in or near the larval habitat. In the case of aquatic species the 

 pupal existence is passed in the earth adjoining the water in which the 

 larva lived, except perhaps in the case of Antocha, which may pupate 

 directly in the water. The larvae of many species of Limnobiini, of 

 Antochini, and in a slightly lesser degree of most other groups, spin a 

 silken case, or cocoon, in which to spend the pupal period. The pupae 

 are more or less active and often wriggle about with great agility. 



On the thoracic dorsum the pupa bears the two breathing horns 

 (fig. 123), which are variously formed in the different groups. They are 

 short, blunt, and flattened in the Limnobiini (fig. 123, b), moderately 

 elongate and cyhndrical in the Eriopterini, the Limnophilini (fig. 123, c 

 and d), and the Tipulini (fig. 123, h), short and truncated at their apices 

 in the Pediciini (fig. 123, e). In the Ptychopteridae (fig. 123, a), one of the 

 two horns is atrophied, while the other is enormously elongated and serves 

 the same function as the extensile breathing tube of the larva. In addi- 

 tion to the thoracic spiracles, the pupae of the Hexatomini (fig, 123, f), the 

 Eriopterini, and some others have conspicuous lateral abdominal stigmata. 



The abdominal segments generally have rows of spines or chitinized 

 points arranged transversely around the caudal margin (fig. 123, h), which 

 help the insect in moving about and serve to keep the tender part of 

 the abdomen from contact with the earth. In the Hexatomini (fig. 123, f) 

 similar spines are developed on the thorax, on the head, and even on the 

 face of the compound eye. In the Cylindrotominae (fig. 123, g) these 

 spines are very highly developed. Smooth-bodied pupae, such as are 

 found in the Limnobiini, are usually inclosed in a silken tube which 

 keeps them from contact with the soil. 



When the insect is ready to transform to the final, or adult, stage, the 

 pupa makes its way to the surface of the earth, to which it remains attached 

 by the caudal part of the abdomen. The thoracic notum then splits 

 down the mid-dorsal region in a straight line, and thru this opening the 

 adult fly emerges. Before the chitin of the body hardens, the insect is 

 very weak and pallid, but in a short time the body expands to its full 

 size and becomes hardened and fully colored, and the dangerous period 

 of transformation is over. 



