760 CHARLES PAUL ALEXANDER 



elongate lobe which is indistinctly pseudo-segmented, in its posterior 

 part being in intimate connection with the abundant fat tissue. 



Respiration and circulation 



The most important literature on the respiratory and circulatory organs 

 is as follows: 



Ptychoptera. Grobben, 1876. 



Dicranota. Miall, 1893:245-248. 



Phalacrocera. Miall and Shelford, 1897 : 351-356. 



Liogma. Mliggenberg, 1901. 



Ctenophora. Anthon, 1908:551-554. 



Holorusia. Kellogg, 1901 a; Comstock and Kellogg, 1904:57-58, 60. 



Tipula maxima. Brown, 1910. 



Tipulinae, Hexatomini (especially Tipula paludosa and Limnophila punctata). Gerbig, 



1913. 

 General articles. De Meijere, 1895; Viallanes, 1880. 



The most important works on the structure of the tracheal system with 

 special reference to the mechanics of the spiracles, are those by Mtiggen- 

 berg (1901), De Meijere (1895, 1902, 1916), Brown (1910), and Gerbig 

 (1913). Miall and Shelford (1897:351-356) discuss in much detail the 

 structure of the heart in Phalacrocera. 



In Eriocera spinosa, which may be considered as typical for this group 

 of crane-flies, there are two principal tracheal trunks which lie in a dorsal 

 position and run almost the length of the body. They are connected 

 across by a very delicate, unbranched, simple, tracheal commissure, and 

 send off branches laterally to supply the various organs of the body. Near 

 the posterior end of the body they are approximated, and just in front of 

 the spiracles they expand into the tracheal chamber Directly cephalad 

 of this chamber the first lateral branch passes off, numbering from the 

 posterior end forward. Branches 2 to 8 are large and much forked. 

 Just after leaving the main tracheal trunks, each of these sends off a 

 ventral branch which supplies the alimentary canal and the fat tissue. 

 Branch 3 supplies the region of the malpighian tubules; branch 4, the 

 posterior part of the stomach; branch 5, the anterior part of the stomach; 

 branches 6 to 8, the esophageal region branch 6 supplying the pro- 

 ventriculus, branch 7 and part of branch 8 the esophagus, and the remainder 

 of branch 8 the pharyngeal region. 



The main part of each lateral branch continues laterad, at its first 

 (anterior) fork sending a branch forward to the next branch, so as to 



