130 GUIDE TO CALIFORNIA INSECTS. 



appearing as a simple bristle on the side of the third joint. 



The venation affords the most important characters used in classification. 

 Great diversity occurs. The marginals are usually well developed, sometimes 

 continuous around the wing. The anterior marginal is oiten called the costal. 

 The primary usually has three branches, the third being sometimes forked. 



The independent vein divides the two basal cells and encloses the discal 

 cell, the large or posterior cross vein closing it externally. The small or an- 

 terior cross vein connects with the primary closing the first basal cell and the 

 posterior basal cross vein connecting with the posterior vein closes the 

 second basal cell. There are usually two posterior veins enclosing the third 

 basal or anal cell. The open cells beyond the basal cells are called the 

 posterior cells the first being opposite the first basal. 



A system of formulae has been devised constructed by listing the bars of 

 the discal cell in the order of their size, numbering them outwardly in order 

 using the even numbers below. The following list includes most of our 

 ganera of crane flies. 



Amalopsis. 3 6 7 (1 2 4) 5* 



Bittacomorpha. 1 — 2 1 



Ctenophora. 3 14 (2 5* 6) 



Dicranorayia 1 — 23 1. 5 — 341652 



Dichranoptyche. 3 4 2 17 5 



Elliptera. 3 2* 1 



Eriocera. 5 4 6 (1 7) 2 3 



Erioptera. 4321 — 421 — 342 5 1 



Geranomyia. 3 4 (1 6) 5 2* 



Helobia. 1 — 3 6 4 2* 5 1 



Holorusip. 3 2 6 4 15* 



Limnobia 2 3 14 5 



Limnophila. .5* 4 3 1 6 (2 7) — 3 2 4 (1 6) 5 — 3 2 5* 4 1 6 7 



Pachyrinia 3 1 —1 



Pedicia 3 2 15 4 



Ptychoptera. 1 2 



Raphidolabis. 3 2 1 — 3241 



Tipula. 3 4 1 5 2 — 3 6 5* (1 7) (2 4) 



Trichocera 2 5* 3 1 6 7 4 



Trimicra. 2 3 4 5 1 



The nomenclature of the veins most used consists in numbering the longitud- 

 inal veins from one to six of which the independent isthe forth. Schiner 

 names these subcostal, radial, cubital, discoidal, postical and anal veins 

 Comstock calls the first three the radius, the remainder the media, cubital and 

 anal. He interprets the posterior basal crossvein as a branch of the cubital 

 vein. 



