42 British Dragonfiies. 



mid-dorsal haiiy tubercles on se<;ments 

 4 to 8, those on the hinder ot those 



segments being smaller depressa. 



b. Less hairy ; legs not quite so stout ; 

 head broader, somewhat circular ; eyes 

 transverse; sharp dorsal spines on 

 segments 4 to 8, not hairy quadriiiiacidaia. 



II. Abdomen more slender, distinctly spotted., canccllatuin [^). 



B. Abdomen with lateral spines ; body not hairy. 



I. Abdomen without dorsal spines. 



a. Abdomen beneath with three longi- 

 tudinal black bands separated by while 

 ones, u]:)j5er surface ornamented with 

 white dots ; spines on segments 8 and i) duhia. 



h. Abdomen unornamented ; spines on 

 segments 8 and 9 short ; head hollowed, 

 size larger striolatinii C). 



II. Abdomen with dorsal spines. 



a. Abdomen unornamented ; dorsal spines 

 on 6 and 7 and lateral ones on 8 and 



9 small ; head arched ; size smaller . . sroticmii. 



b. Lateral spines on segment 8 long, on 

 9 very long ; head flat ; eyes large ; 



tibia; naked, size larger saiiguiiicnm {?). 



c. Abdomen posteriorly truncate ; lateral 

 spines on segments 8 and 9 very small ; 

 tibiae hairy; antennas conspicuous, basal 

 joints stout ; head pentagonal. 



1. Head and eyes small ; dorsal 

 hook present on segment i) ; 

 lateral margins of same segment 



hairy inctalliia. 



2. Head and eyes larger; dorsal 

 hook absent, or nearly so, on 

 segment 9 ; lateral margin of 



same segment entire . . . . crnea. 



^SCHNID^E. 



A. Antennae four-jointed, flattened ; fore- and 

 mid-legs with tarsi two-jointed ; mask not 

 covering mouth, flat ; legs strong, formed 

 for burrowing ; abdomen lanceolate, flat ., '7'iihatissiiiiifs . 



