112 DEAGONFLIES [CH. IV 



Bechstein have noted cuckoos catching them both upon 

 the wing and when at rest upon the reeds. I myself have 

 seen the remains of Agrionids in the webs of Spiders 

 (Agelena labyrinthica) spun in the gorse bushes beside a 

 pond, and have often observed that the same weak-winged 

 Dragonflies are caught and digested by the leaves of the 

 Sundew (Drosera rotundifolia). 



A small red mite, an Acarid, is occasionally (frequently 

 in the genus Sympetrum) found as an external parasite 

 upon the thorax. 



CLASSIFICATION OF BRITISH DRAGONFLIES 1 . 



Dragonflies may be divided into two chief groups by the form 

 and resting position of the wings. 



(51) 1. Group I. ANISOPTERIDES. Front wings differ from the 

 hind in shape, the latter being usually broader at the 

 base : a small " accessory membrane " is present at 

 the base of each wing on the posterior side close to the 

 junction with the thorax. When at rest the wings are 

 held spread out parallel with the dorsal and ventral 

 surfaces of the body. The eyes meet on top of head 

 (except Gomphus vulgatissimws). The 10th abdominal 

 segment of the male has only one ventral appendage. 



This group includes the two Families (A) Libellulidce 

 and (B) JEschnidce. 



They are distinguished from one another by the 

 direction of a certain "cell," known as "the triangle," 

 in the front wings. 



1 Lucas, British Dragonflies, London, 1900. 



