The Imago. 55 



For descriptive purposes the junction of the thorax 

 and abdomen is looked upon as the centre of an insect, 

 and that extremit}- of ever}- part or appendage nearest to 

 the centre is spoken of as basal, the opposite extremit)- 

 being known as distal or apical. The terms anterior 

 or fore, and posterior or hind, have reference to position 

 near or remote, respectiveh', from the front of the head. 

 Longitudinal refers to an\-thing l\-ing in the length of 

 the insect — along or parallel to its main axis ; trans- 

 verse means across the bod}' from side to side. That 

 is the right side of an insect which is on the right- 

 hand side to a person looking along the insect from 

 the rear to the head, as it lies on its ventral surface. 



ANALYTICAL TABLES. 



For purposes of classification chiefl\-, the following 

 tables have been drawn up. The\' generalh' refer to 

 very prominent features, and must be applied with 

 caution to any but the British Dragonfly Fauna. To 

 identif}' an insect it must first be referred to its proper 

 famih', then sub-family, genus, and species. Deviation 

 from this order may lead to confusion. 



L — Table of Families. 



A. Wings dissimilar, hind-wiiif^s usually broader 

 at base, kept spread out flat in repose ; 

 an accessory membrane present ; males 

 with one inferior anal ajipendage ; eyes 

 meeting on top of head (except Gomplms). 

 [axisopterides.] 



a. Abdomen with lateral carina? ; females 

 without ovipositor ; triangle of fore- 

 wings with its long axis transverse, of 

 the hind-wings longitudinal LIBELLULIDiE. 



